there is still something wrong:

I’ll try again – please read it carefully
The menu you see above as a text menu and the menu you see in the hamburger menu have the same source but different selectors. So you don’t need to set up a media query to hide the logo in the top text menu. This is particularly advantageous in your case, as given the nature of your text menu, it would certainly be better to display the hamburger menu earlier (1085px) than would be possible at 768px. Your text menu overlaps the main logo long before it displays the hamburger icon.

for having an earlier hamburger icon you only need here a media query setting:

@media only screen and (max-width: 1085px) {
    #top #header .av-main-nav > li.menu-item  {
        display: none !important;
    }
    #top #header .av-burger-menu-main {
        cursor: pointer;
        display: block !important;
    }
}

Remove all media query settings for your only_mobile logo from your Quick CSS, with the exception of the existing global rule.
(This is why it already works for the footer area.)

.only_mobile {
  display: none;
}

you now only have to show it again for the hamburger menue:

#av-burger-menu-ul .only_mobile {
  display: block;
}

thats all.

btw: here are the selectors for your logos inside your menues:
top text menue: #avia-menu .only_mobile
hamburger menue: #av-burger-menu-ul .only_mobile
footer menue: #menu-main-menu .only_mobile

yes – the checked status is for having not a fixed header_meta (top bar)

All my attempts to remove these automatic br tags failed. So you could just use it like this:
<strong>Validation & Calibration</strong><ul><li>Supply and exhaust air volumes</li><li>Room pressure differential</li><li>Pressure gauges and monitors</li><li>Air changes per hour</li><li>Incubators and scales</li><li>Refrigerators and freezers</li></ul>

we do not want to get rid of intentionally set br tags – but the automatic set br tags are a problem _ thats why i set on my testpage that oneliner !

The bullits are set on my test page because the ul and li elments do have them – no manually placed bullits.

i do not know why it does not work on your installation.

please do clear all cachings

do not rule it by media query but only with the different selectors

you have still this inside your css: – please remove it

@media only screen and (max-width: 767px) {
  .responsive #top .av-main-nav .menu-item {
    display: none;
  }
}

this works great on DEV Tools for your staging page – if you got different selectors or settings for the page itself – then you have to give us the final link

#avia-menu .only_mobile {
  display: none;
}
#footer-page .only_mobile {
  display: none;
} 

and do not rule it by media query but only with the different selectors:

#avia-menu .only_mobile {
  display: none;
}

and for the footer:

#menu-main-menu .only_mobile {
  display: none;
}
/ *** or ***/
#footer-page .only_mobile {
  display: none;
} 

because the menu on desktop got an ID and the burger menu is inside .av-burger-overlay and got the id: av-burger-menu-ul

by the way: I can understand it in the case of the hamburger menu, because here it is a copy of the main menu.
But you must have created your footer menu as an extra menu. Why did you put the logo there?

The Demo: enfold-business-flat has on all pages a transparent header. !!!
The transparency logo is shown then. So did you have inserted an alternate logo on :

on the rest of your pages you do not see any logo because the default logo for transparency on that logo is white – and all pages of your page have a white color-section on top.

Unfortunately, WordPress is very stubborn when it comes to automatically setting br tags. You could use the following in the excerpts:

<strong>Validation & Calibration</strong>
<ul>
	<li>Supply and exhaust air volumes</li>
	<li>Room pressure differential</li>
	<li>Pressure gauges and monitors</li>
	<li>Air changes per hour</li>
	<li>Incubators and scales</li>
	<li>Refrigerators and freezers</li>
</ul>

All my attempts to remove these automatic br tags failed. So you could just use it like this:

<strong>Validation & Calibration</strong><ul><li>Supply and exhaust air volumes</li><li>Room pressure differential</li><li>Pressure gauges and monitors</li><li>Air changes per hour</li><li>Incubators and scales</li><li>Refrigerators and freezers</li></ul>

see on “listpoints” post : https://webers-testseite.de/masonry-blog/

do you replaced the “your-cpt” with the name of your CPT. (f.e.: event …)

And you used the new code of ismael ? – because the ( ‘post_type’ => ‘any’,) is important for using it with CPT …
or explicitly name it as a post type:

how did you embed your cpt to masonry?

function custom_masonry_cpt_with_sticky($query, $params) {
    $query['post_type'] = array('post', 'portfolio', 'your-cpt'); 
    
    $query['ignore_sticky_posts'] = 0;
    
    // Optional: if you like to adjust it
    // $query['posts_per_page'] = 12;
    
    return $query;
}
add_filter('avia_masonry_entries_query', 'custom_masonry_cpt_with_sticky', 10, 2);

and then try:

function custom_masonry_sticky_first($query, $params) {
    $query['post_type'] = array('post', 'portfolio', 'your-cpt');
    
    // Sticky Posts first
    $sticky = get_option('sticky_posts');
    
    if (!empty($sticky)) {
        $query['post__not_in'] = isset($query['post__not_in']) ? array_merge($query['post__not_in'], $sticky) : $sticky;
        
        $query_sticky = $query;
        $query_sticky['post__in'] = $sticky;
        $query_sticky['ignore_sticky_posts'] = 1;
        unset($query_sticky['post__not_in']);
 
        $query['_sticky_query'] = $query_sticky;
    }
    $query['ignore_sticky_posts'] = 0;
    return $query;
}
add_filter('avia_masonry_entries_query', 'custom_masonry_sticky_first', 10, 2);

enter your CPT for ” your-cpt” in the snippets.

next the first section of your homepage
I can’t quite understand how it was set, because it gets completely out of hand in responsive cases.
maybe you have set a column to a min-height value that is not good for mobile view.

try – and read comments:

@media only screen and (max-width: 989px) {
  /*** depends on if a header_meta is present and the height of it ***/
  /*** header_main plus header_meta height value is needed ***/
  #header {
    position: fixed !important;
    height: 120px !important;
    max-height: 120px !important;
  }
  
  /*** synchronise with header height value ***/
  .responsive.html_header_top #top #main {
    padding-top: 120px !important;
  }
}

/*** necessary – because your header_meta will then have two lines   ***/
@media only screen and (max-width: 521px) {
  #header {
    position: fixed !important;
    height: 140px !important;
    max-height: 140px !important;
  }
  /*** synchronise with header height value ***/
  .responsive.html_header_top #top #main {
    padding-top: 140px !important;
  }
}

Ismael’s rules don’t work properly because a selector that I also thought was present is not there: html_mobile_menu_tablet
My notes on this case of sticky headers on mobile devices always included this selector too.

it is the place where you have entered the text for that button.:
Open the slide itself – a new popup then will show the options for that slide. Click on the advanced tab. There should be a link settings – on the right side of the label there is the color of that button. Sadly there is no custom color with color picker option – but a lot of alternatives to your given choice.
If you have set the on styling tab to show “Use first slides caption as permanent caption” then you had to open the first slide.
_______________

If that’s not enough, you would have to set the background color via CSS.
better way is to do it via a custom class on your slider – but try:

#top.page-id-1104 .avia-slideshow .avia-slideshow-button {
  background-color: #026538;
}
#top.page-id-1104 .avia-slideshow .avia-slideshow-button:hover {
  background-color: #719430;
}

It probably wasn’t that important ;)

Are you using this solution?
https://kriesi.at/support/topic/image-title-on-hover/#post-1490549

because there the selector is for all elements with title attribute ( *[title] ) – so this will include icons

you have to pay attention – there is a
masonry for posts on : Content Elements Tab
masonry and gallery for images on : Media Elements

on your example page there is the use of portfolios.