check this page with your iPhone: https://webers-testseite.de/sam/
if you have convinced yourself that it works on mobile devices – I will take my site down again.

on my iPhone i got this message from your page: “Please set a mobile device fallback imgage for this video in your wordpress backend.”
so now i recognise that you use the fullwidth-slider.

i used for the video a color-section with video background. And set on
“Section Minimum Height – …(responsive section) to 56% (9/16*100)”. ( on a 16/9 video)

Why do you have that text as double content?

Lets try if a css only solution will do the job:

Do not create that extra text section. This means: your 1/3 column on the left – the 2/3 column with your text on the right. As probably before, move the line column upwards (-200px) using the setting via Advanced – Position relative in the Row Settings – Row Screen Options setting and let the columns wrap at 989px. Give the column with the image its own meaningful class, e.g.: hide-on-smallscreens.

Now insert it into the Quick CSS:

@media only screen and (max-width: 989px) {
 #top .flex_column.hide-on-smallscreens {
    display: none !important;
  }
  #top .flex_column.hide-on-smallscreens + .flex_column {
    width: 100%;
  }  
}

maybe it is better to shift the image via position relative.

so it is not your own page? Its for a different page?

try:

@media only screen and (min-width: 768px) {
  #footer .container {
    display: grid;
    gap: 20px;  
    grid-template-columns: repeat(3, 1fr);
    justify-content: space-between;
  }
  #footer .container .flex_column {
    width: unset;
    padding: 0;
    justify-self:center;
  }
  #footer .container .flex_column:nth-child(1) {
    justify-self: left;
  }
}

if you like to have the first column to be centered in its container too ( the text preserves align left ) – then erase the last rule for first child column

I have added to the code that the slider reacts to smaller screen widths – i.e. deviates from the number initially set via the user class.

in that part:

// Responsive Anpassung der Spaltenanzahl für verschiedene Bildschirmgrößen
if (window.innerWidth < 480) {
    currentVisibleColumns = 2;
    console.log('Custom Slider: (updateResponsiveColumns) Screen width < 480px. Setting visible columns to 2.');
} else if (window.innerWidth < 768) {
    currentVisibleColumns = 3;
    console.log('Custom Slider: (updateResponsiveColumns) Screen width < 768px. Setting visible columns to 3.');
} else if (window.innerWidth < 1024) {
    currentVisibleColumns = 4;
    console.log('Custom Slider: (updateResponsiveColumns) Screen width < 1024px. Setting visible columns to 4.');
} else {
    currentVisibleColumns = initialColumnsFromClass;
    console.log('Custom Slider: (updateResponsiveColumns) Screen width >= 1024px. Using initial columns from class:', initialColumnsFromClass);
}

PS: you can only implement something like this properly with the help of AI. I just know how to prompt the right questions.
;)

do you have a yoast seo installed and perhaps a premium version? Because there is a beta tool:

but i think the allready placed p-tags had to be removed manually
maybe other plugins with AI support can cause this too (Rank Math or an AI content helper)

you can edit the element itself. On WPML there should be for each language a separate page.
Open the element and look for : Content – Buttons : “Before Button Text” and. “After Button Text” – you can enter your own phrase on that. And because of separate pages for each language you can have your own translated text there.

on default there are allready these lines : https://kriesi.at/themes/enfold/portfolio/

maybe you set it to display: none ? search for selector .avia-menu-fx

you then can influence by – f.e.:

#top .header_color .avia-menu-fx {
  height: 4px
}

#top .header_color.av_header_transparency .menu-item a:hover .avia-menu-fx {
  background: red
}

#top .header_color:not(.av_header_transparency) .avia-menu-fx {
  background: green
}

da es immer hierzu eine Berechtigung geben muss seitens der Seite die eingebunden werden soll – wird es in den seltensten Fällen gehen.
Es sei denn diesen Seiten ist es komplett egal was Sicherheitsfragen anbelangt. Da wirst du heute aber kaum noch Seiten find, die alle Tore und Türen öffnen. Einträge wie:
Header set Access-Control-Allow-Origin: * oder

Eine Seite einlesen und selbst Listen erstellen – via php ?. Wenn Du z.B. auf einer Seite all h3 Überschriften sammeln möchtest und diese als Liste auf deiner Seite dann ausgeben möchtest.

z.B:

function external_headings_shortcode( $atts ) {
    // Standardattribute festlegen
    $atts = shortcode_atts(
        array(
            'url'  => '', // Die URL der externen Seite
            'tag'  => 'h2', // Der HTML-Tag der Überschrift (z.B. h1, h2, h3)
        ),
        $atts,
        'external_headings'
    );

    $url = esc_url_raw( $atts['url'] );
    $tag = sanitize_text_field( $atts['tag'] );

    // Überprüfen, ob eine URL angegeben wurde
    if ( empty( $url ) ) {
        return '<p style="color: red;">Fehler: Bitte gib eine URL für den Shortcode "external_headings" an.</p>';
    }

    // Überprüfen, ob der Tag gültig ist (z.B. h1-h6)
    if ( ! preg_match( '/^h[1-6]$/', $tag ) ) {
        return '<p style="color: red;">Fehler: Ungültiger HTML-Tag. Bitte verwende h1 bis h6.</p>';
    }

    // Inhalte von der externen URL abrufen
    $response = wp_remote_get( $url );

    // Fehlerbehandlung
    if ( is_wp_error( $response ) ) {
        return '<p style="color: red;">Fehler beim Abrufen der URL: ' . $response->get_error_message() . '</p>';
    }

    $body = wp_remote_retrieve_body( $response );

    // HTML parsen
    $dom = new DOMDocument();
    // Fehler beim Parsen unterdrücken (z.B. für nicht-wohlgeformtes HTML)
    libxml_use_internal_errors( true );
    $dom->loadHTML( $body );
    libxml_clear_errors(); // Fehler wieder löschen, um Speicher freizugeben

    $xpath = new DOMXPath( $dom );
    $headings = $xpath->query( '//' . $tag ); // Alle Elemente des angegebenen Tags finden

    $output = '';

    if ( $headings->length > 0 ) {
        $output .= '<ul>';
        foreach ( $headings as $heading ) {
            $output .= '<li>' . esc_html( $heading->textContent ) . '</li>';
        }
        $output .= '</ul>';
    } else {
        $output .= '<p>Keine ' . esc_html( $tag ) . '-Überschriften auf der Seite gefunden.</p>';
    }

    return $output;
}
add_shortcode( 'external_headings', 'external_headings_shortcode' );

wird dann z.B. so auf der Seite eingebunden:[external_headings url="https://eine-domain-url" tag="h3"]

I think the partner/logo element comes closest to this. However, the slide behaviour differs slightly from that on your example page. Here the whole block with the partner logos slide out of the image; this means that if you place five logos next to each other, for example, they are replaced manually or automatically by the next five logos. They are not moved one logo at a time as you did.
P.S. This slide option would certainly be useful!

maybe a mod knows a better way to shift the quick css input field to top of the styling options section.
(I was familiar with that filter because I had used it before to place a new input field for Apple Touch icons behind the favicon.)

/**
 * Custom function to reorder Enfold theme options.
 * Moves the 'Quick CSS' input field above the 'Color Scheme' selector.
 * Assumes both 'quick_css' and 'color_scheme' elements are always present.
 */

function custom_enfold_reorder_styling_options($avia_elements) {
    $quick_css_option = null;
    $color_scheme_option_index = -1;
    $quick_css_option_index = -1;

    // Find the 'quick_css' and 'color_scheme' options and their original indices.
    foreach ($avia_elements as $index => $element) {
        if (isset($element['id']) && $element['id'] === 'quick_css') {
            $quick_css_option = $element;
            $quick_css_option_index = $index;
        }
        if (isset($element['id']) && $element['id'] === 'color_scheme') {
            $color_scheme_option_index = $index;
        }
    }

    if ($quick_css_option_index > $color_scheme_option_index) {
        // Remove the 'quick_css' option from its original position.
        array_splice($avia_elements, $quick_css_option_index, 1);
        array_splice($avia_elements, $color_scheme_option_index, 0, [$quick_css_option]);
    }

    // Return the modified array of theme options.
    return $avia_elements;
}

// Hook into Enfold's option page data initialization filter.
add_filter('avf_option_page_data_init', 'custom_enfold_reorder_styling_options', 10, 1);

Es wird so nicht funktionieren. Man könnte sogar auf deiner Seite das in einer Lightbox aufrufen. Hier wäre dann ein Popup vom type:’ajax’ nützlich. – Leider hängt das Einbinden von externen Seite sehr davon ab, was die abgefragte Seite für Sicherheiten eingerichtet hat:

Fehlermeldung ist dann z.B.:

Quellübergreifende (Cross-Origin) Anfrage blockiert: Die Gleiche-Quelle-Regel verbietet das Lesen der externen Ressource auf https://www.kleinanzeigen.de/s-anzeige/moderne-doppelhaushaelfte-mit-keller-in-ruhiger-lage-kueche-geschenkt-/3077951470-208-6482/. (Grund: CORS-Kopfzeile ‘Access-Control-Allow-Origin’ fehlt). Statuscode: 403. 2

Das kannst Du eben nicht beeinflussen. Auch ich richte meist auf meinen Seiten genau das ein, das niemand die Seite einbinden kann.
via htaccess bei apache Servern.

Die gegenseite müsste dann deiner Seite erlauben:
Header set Access-Control-Allow-Origin "https://deine-domain.de"

Wenn man via iframe eine Seite einbinden will muss die Gegenseite die X-Frame-Options für dich erlauben
bzw. : moderner den CSP Header so einrichten, das die Seite als frame-ancestor gelistet ist.

Also – wenn es denn Eure Bilder sind – lade die auf deiner Seite hoch und gestalte dann mit Enfold deine Galerie

this could be a nice usage – but the stickyness only belongs to the direct parent container.

https://webers-testseite.de/sticky-elements/

Some explanations are shown here:
https://webers-testseite.de/sticky-sidebar/

If you use more specific selectors, you can style “strong” differently.

if you want it only on some words in a textblock you had to use the way above from Rikard.
for example if you like to have a different color for them only on one page – use the page ID :

#top.page-id-12345 strong {
  color: black;
}

sometimes it might be necessary to have an !important on the value. (black !important;)

PS: if you are editing text-blocks the editor could do that for you
this will create an inline-style:
<span style="color: #ff0000;"><strong>Important</strong></span>

see here on very small screens: https://webers-web.info/datenschutz/
that sidebar menu on the left goes to a hamburger on top right on small screen width.

you see on the link above (https://jonsuh.com/hamburgers/) – and (on enfold main burger DOM ) what are the class names – i used them too – because then a predefined look is allready present.:
and the script to manage the burger is allready loaded

(page-id-3 – is my privacy page)

add_action('ava_after_main_menu', function() {
	if ( is_page(3)){
		echo '<nav class="datenschutz-menu" role="navigation">';
		echo '<div class="container av-menu-mobile-active">';
		echo '<a href="#" class="mobile_menu_toggle no-scroll" aria-hidden="true" data-av_icon="" data-av_iconfont="entypo-fontello"><span class="av-current-placeholder">Datenschutz</span>';
		echo '<span class="subnav-hamburger subnav-hamburger--spin-r"><span class="subnav-hamburger-box"><span class="subnav-hamburger-inner"></span></span></span>';
		echo '</a>';
		echo do_shortcode('[menu name="datenschutz"]');	
	 	echo '</div>';
		echo '</nav>';
	}
});

on that line: echo do_shortcode('[menu name="datenschutz"]'); you see the usage of that menu shortcode

now i got that extra subnav-hamburger (this name is set by me – it only reminds me that this is subnavigation on privacy page )
now i have to have the same behaviour on that second burger menu:

function subnav_hamburger_first(){
if(is_page(array( 3))){ 
?>
<script>
(function($){
    var $subham = $(".mobile_menu_toggle");
    $subham.on("click", function(a) {
		$subham.find(".subnav-hamburger").toggleClass("is-active");
		$subham.next(".menu-datenschutz-container").find('#menu-datenschutz').toggleClass("av-open-submenu");
    });
	$('#menu-datenschutz li').on("click", function(b) {
		$(this).addClass('selected').siblings().removeClass('selected');
		$(this).parents('#menu-datenschutz').toggleClass('av-open-submenu');
		$(this).parents('.av-menu-mobile-active').find('.subnav-hamburger').toggleClass('is-active');
	});
})(jQuery);
</script>
<?php
}}
add_action('wp_footer', 'subnav_hamburger_first');

This is not a trivial request, which is why there are several paid plugins available. To grasp the complexity of a multilevel burger menu, take a look at the avia-snippet-hamburger-menu.js code.