The website loads invisible elements.

what you can do – ( not with enfold specific tools )!

do not set the background-image with enfold color-section settings.
put into the color-section on top a code-block element with this content
(adjust to your path and videos):

See Solution on next posts

Edit: here is the solution with working separators on those color-sections

the color-section that should react like this:
give a custom class to it: av-video-section
give a background-color to it that does not disturb your video switch (not white – something that fits to your video content
place a codeblock element on top of your color-section ( codeblock to content – not as codesnippet)

<video class="responsive-background-video" 
        autoplay muted loop playsinline
        data-video-mobile="path/to/mobile.mp4"
        data-video-desktop="path/to/desktop.mp4">
    <source src="" type="video/mp4">
</video>

this to your quick css:

.responsive #top #wrap_all .avia-section.av-video-section {
  position: relative;
  overflow: hidden; 
  min-height: initial; /* taken from Enfold section setting  */
}
.responsive #top #wrap_all .avia-section.av-video-section .container {
  position: relative;
  z-index: 1;
  max-width: 100% !important;
  width: 100% !important;
  padding: 0 !important;
}  
.responsive #top #wrap_all .avia-section.av-video-section .responsive-background-video {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover !important;
  z-index: 0;
  min-height: inherit; /* transfer from Enfold section setting  */
}
.responsive #top #wrap_all .avia-section.av-video-section .avia-divider-svg {
  z-index:2;
}
.responsive #top #wrap_all .avia-section.av-video-section .avia-divider-svg.avia-to-front {
  z-index:100;
}

the snippet for child-theme functions.php

function custom_responsive_background_video_script() {
?>
<script>
(function($) {
    "use strict";

    $(document).ready(function() {
        $('.responsive-background-video').each(function() {
            const video = this;
            const $video = $(video);
            const source = video.querySelector('source');
            const win = $(window);
            
            // Get video paths from data attributes
            const mobileVideo = $video.data('video-mobile');
            const desktopVideo = $video.data('video-desktop');
            
            if (!mobileVideo || !desktopVideo) return;
            
            function updateVideoSource() {
                const isMobile = win.width() < 768;
                const newSrc = isMobile ? mobileVideo : desktopVideo;
                
                if (source.src.indexOf(newSrc) === -1) {
                    source.src = newSrc;
                    video.load();
                }
            }
            
            // Initial load
            updateVideoSource();
            
            // Resize handling
            win.on('debouncedresize', updateVideoSource);
        });
    });
})(jQuery);
</script>
<?php
}
add_action('wp_footer', 'custom_responsive_background_video_script', 999);

see example page with divider : https://webers-testseite.de/background-video/

have you followed my link to the testpage? There is the video in the “background!” you can see the layout of that in the placed image below.
The rest is the css you need.
PS: Hope Mike could help you – because as a participant i can not see private content area.

Are these self-hosted videos? How large are the files?