Since Version 5.6.9 there is an enfold embedded duplicate option – if you hover the list. Or in edit mode – you see on the right side : “copy to a new draft”
Since that version – i have deleted those extra plugins you mentioned above.

yes – or place a whitespace separator to that cell – and set on advanced tab the “Element Visibility”.

so here is my version of your logo:
https://webers-testseite.de/motive-agency.svg

on looking to the svg with dev tools ( or download it and see in a good text editor) you see that i renamed the standard classes st to ma – and even the gradient is build via class – so changing it from outwards css (quick css) is easy even for the gradient stop-colors.

try:
(but as mentioned above – if you have defined a standard transparency logo on enfold options – you do not need to add that header_class)

function av_change_alt_logo_img($header){
    if(is_page(1313)) {
	$header['header_class'] .= ' av_alternate_logo_active';  
        $header['header_replacement_logo'] = 3951;
    }
    return $header; 
}
add_filter('avf_header_setting_filter','av_change_alt_logo_img');

the header class to activate the transparency logo is set by enfold to: av_alternate_logo_active
the page-id of your about page is : 1313 isn’t it ?
the logo ID – can not proove it from dev tools.

this sub logo is called header_replacement_logo and could be changed via avf_header_setting_filter:
But: there must be something to replace – means : a transparency logo had to be defined on enfold options – then it could be replaced by a different logo.
on handling svg files just use the ID of that Logo ( look to your media library in list mode). Or look to url window in grid mode
on inserting/replacing png, jpg or gif use the url to replace the standard logo and not the ID

function av_change_alt_logo_img($header){
   if (is_page('about')) {
        $header['header_replacement_logo'] = 44238;
    }
    return $header; 
}
add_filter('avf_header_setting_filter','av_change_alt_logo_img');

PS: if the named page does not work use the ID of that page (without quotes)

next : if you do not want to declare a transparency options logo on enfold options- then only activate the transparency logo for that page before adding the logo:

function av_change_alt_logo_img($header){
    if(is_page('about')) {
	$header['header_class'] .= ' av_alternate_logo_active';
        $header['header_replacement_logo'] = 44238;
    }
    return $header; 
}
add_filter('avf_header_setting_filter','av_change_alt_logo_img');

_______________

PPS: this is a good way to replace the logo (standard logo) with an svg file :

function av_change_logo($logo){
  if(is_page(123)) {
    $logo = 456;  // ID of the svg Logo
  }
  return $logo;
}
add_filter('avf_logo', 'av_change_logo');

The assumption is that it could be due to a plugin. Could it be the VFB Pro plugin that is not interacting properly?
To find out, I would first deactivate all plugins, then regenerate all caching (browser caching as well as Enfold Merging). Check whether this is still the case with the images. If the problem is no longer present, reactivate one plugin after the other and check when the error occurs again.

PS: on trying to insert a media file to your text editor – are there any errors in the console that you can post here.
Just open the dev Tools of your browser – and open the console log. See if there are errors when trying to insert a media file.

i can not believe that the other three shows no marks – and one does.
Anyway try that snippet in your child-theme functions.php from: https://pastebin.com/k0f385TJ

what do you see if you click on the first mp3 Commercial on the right side at “Attachment Details” then.
Especially on Title

so you are not using the alb element “blog posts” to show the content – but you have declared a page on : Enfold Child – Theme Options : “Where Do You Want To Display The Blog”. – and on Enfold Child – Blog Layout – you set the blog Layout to “Grid Layout”

try in your child-theme functions.php:

add_filter("avf_post_slider_args", function($atts, $context) {
  if( $context == "index" ) {
    $atts['type']  = 'grid'; 
    $atts['columns']  = 3;
    $atts['preview_mode'] = 'custom';
    $atts['image_size'] = 'entry_with_sidebar';
  }
  return $atts;
}, 10, 2);

other contexts in this could be : archive or tag – you can change the columns here too

Wow – thank you on that!

By the way – it only looks like the countdown if the css in question is loaded. If you have selected “Load only used elements (recommended)” in enfold options – and you have never used it in your installation – then the corresponding css is not loaded. Simply create a draft page somewhere on which the countdown is used.

And main point is – no img tag is used – images are background-images.

Do you realy mean spacings ? those spaces between words? or do your mean line-breaks set by <br>
this is a known issue but not on enfold – it is a wordpress “feature” ;)

To avoid that Enfold got this extra button on text editor:

it is then set as : <br class="avia-permanent-lb" />

now you can see on that example page – that i can influence the inline svg logo to have different fill colors if the header is transparent.

in this case i do not use the transparency logo on enfold options. – i just switch the fill color for that case:

.html_header_transparency #header:not(.header-scrolled) .fillColor {
  fill: #FFF;
}

by the way – on your page – i wouldn’t try to set the svg dimension via height – because this is calculated by the shrinking script.
just set a width ( absolute value)

.logo svg {
  /*** margin-top: 10px; ***/
  /*** padding: 10px; ***/
  width: 350px;
  /*** height: auto; ***/
}

so get rid of margin-top, padding and height

So try to upload that Font via : Custom Font Manager ?

how did you transform f.e. the ttf or otf files to web-fonts?
My Copperplate here is the Pro Version and otf files.

you can do that f.e. on : https://transfonter.org/
i think ttf and woff2 would be sufficiant.

by the way: https://similarfont.io/2-google-fonts-similar-to-copperplate

but this is not a pure svg file – it has an embedded image file ( as data:image/png;base64 ) – the advantage of svg is the vectorbased curves.

The embedded Image in your file is superflous. Here is a cleaned version of your logo:
https://webers-testseite.de/gonowjets.svg

you see on the xml code of that svg a group class : fillColor
so you can now colorize that logo via quick css:

.fillColor {
  fill: #FFF;
}

see in action on : https://webers-testseite.de/gonowjets-2/
with:

#top .logo svg {
  width: 300px;
}

ps: the svg does not shrink with the header because it fits with the given width even in the shrinked header.
if you do not set the svg width – it will shrink but then it is very big of course.