if you choose the header style: logo center – navigation below it would be possible.
in this case the navigation will be in an extra container: header_alternate not inside logo container
and set for: Menu Items For Desktop to icon

then try :

.av-burger-menu-main.menu-item-avia-special {
  position: fixed !important;
  bottom: 0;
  left: 10px;
  padding: 10px;
  z-index: 1001 !important;
}

.av-hamburger {
  padding: 15px 8px;
  display: inline;
  background-color: rgba(255,255,255,1);
  box-shadow: 0 0 15px -5px #333
}

#header, #header_main {
  height: 0px !important
}

@media only screen and (max-width:767px) { 
 .responsive #header_main_alternate {
  display: block
 }
}

.container.av-logo-container, 
.header_bg {
  display: none !important;
}

.responsive #main {
  padding-top: 0 !important
}

besides that – you can exclude specific css or js files from being merged.

f.e. on an installation i need to exclude the recaptcha script from beeing merged.

function avia_exclude_files_from_compression($excluded_files){
  $exclude_js = array( 'avia_google_recaptcha_front_script');
  $excluded_files['js'] = array_merge($excluded_files['js'], $exclude_js);
  return $excluded_files;
}
add_filter('avf_exclude_assets', 'avia_exclude_files_from_compression', 10, 1);

maybe this will work too:

function my_avf_exclude_assets( array $exclude_files ){
	/**Add CSS to exclude*/
	$exclude_files['css'][] = 'my-css-file';		//	use the enqueue name	
	/*** Add js to exclude*/
	$exclude_files['js'][] = 'my-js-file';			//	use the enqueue name	
	return $exclude_files;
}
add_filter( 'avf_exclude_assets', 'my_avf_exclude_assets', 10, 1 );

this comes from your search-box : View Our Stock
you embedded that script via code-block – maybe you try better to embed it via child-theme functions.php
i don’t know where inline js is loaded – but if it loaded before jQuery is present then an error message would certainly be expected.
Do you load your jQuery in the footer? See: Enfold Child – Performance : “Load jQuery In Your Footer” Option

Edit: if i look to that ( not minified ) script : https://apsr.autoplay.co.nz/Content/js/loader.search.box.js it seems that the script is loading its own jQuery from different external sources – maybe that comes into conflict with Enfold jQuery.

thanks Ismael – that works –

I already suspected that I had to work with array_reverse, only I didn’t find the place in the code where to put it.
Don’t you think it would be better to set this as default generation of the css for the urls?

Maybe you can use the pseudo element :marker
( but IE will not respect that rule – edge does – so who cares )
by: https://css-tricks.com/almanac/selectors/m/marker/

li::marker {
  color: red;
}

if you like to have this only on selected text-blocks – give a custom class to the text-block and

.custom-class li::marker {
  color: red;
}

these are: Selector Level 4 – so like :any-link etc. all older Browsers will ignore those settings.

This is the real purpose of the first screen you can adjust. For exactly the reasons you stated above, I usually only change the second and third screens. This way you don’t necessarily have to set the last two. Because in the rarest of cases, these settings are also applied to mobile devices. By leaving the first setting, the default values will be applied.

Well – i use nearly almost the quick css – the only thing that always bothers me is that the window widths are limited. I’m now working on a high-resolution 4k 32” monitor. So I want to be able to take advantage of that.

I put in my child-theme functions.php file:

function admin_head_mod() {
echo '<style type="text/css">
  #avia_options_page .live_bg_wrap .main_h3 { font-size: 36px !important; }
  #avia_options_page .content_p, #avia_options_page .bg2 { font-size: 24px; }
  #avia_quick_css .avia_description {float: none;margin-bottom: 20px !important;padding-left: 0 !important;width: 98%}
  #avia_quick_css .avia_control {float: left;max-width: 98% !important;width: 98% !important}
  .avia_footer_links li {float: left;padding-right: 20px}
  .avia_footer .avia_footer_save {float: left}
  .avia_reset {display: none !important } 
  #avia_options_page { max-width: 3000px!important}
</style>';
}
add_action('admin_head', 'admin_head_mod');

however, the latest enfold versions now have a “Theme Reset All Options” button on the import/export tab – I already include this in the code as seen above.

/***  standard logo visible on transparency  ***/
#top.page-id-591 .av_header_transparency.av_alternate_logo_active .logo a > img, 
#top.page-id-591 .av_header_transparency.av_alternate_logo_active .logo a > svg {
  opacity: 1;
  filter: alpha(opacity=1);
}

/*** font color on transparency  ***/
#top.page-id-591 #header.header_color.av_header_transparency .av-main-nav > li > a .avia-menu-text {
  color: #000
}

/*** font color after scrolling down ***/
#top.page-id-591 #header.header_color .main_menu ul:first-child > li > a {
  color: #000
}

by the way: only in very rare cases it is necessary to use the custom.css, mostly it is enough to use the quick css for the settings.
and please copy&paste the code above – it is important to preserve non-spaces between some classes at the same element. ;)

see here with break-inside : https://enfold.webers-webdesign.de/multicolumn-text-block/

allthough Rikards css is correct – the enfold original css has two ID’s in the selector. An ID has a much more higher specifity than the classes – so try:

#top.page-id-591 #header.header_color.av_header_transparency .av-main-nav > li > a .avia-menu-text {
   color: #000
}

do you need any additional help?

But do you use google gstatic? Google Maps also loads this font – and maybe all Google Addons will do that (Google Analytics etc.).
there are many scripts on the internet to hamper loading Roboto –
but the loading of the fonts should be the smaller problem from the GDPR point of view. Anyone who prevents these Google services from being loaded when the page is called up until an opt-in takes place should be GDPR compliant. Before that, the font will not be loaded either. Perhaps you should explicitly point this out in your privacy policy.
f.e.:

Anyone who has integrated Google Fonts via the Google server or the Fonts API must accept that the user data of their visitors will be passed on to Google. However, in our opinion, this is not permissible without your consent.

Therefore, we integrate the Google Fonts locally. This means that the Google Fonts are loaded directly from our server and no longer via the Fonts API. In this way, no user data is sent to providers outside the EU.

Permission to use the fonts locally has been obtained from Google.

However, if you agree to the use of one of the Google Services (Maps, Recaptcha, Analytics etc.); Google also loads its own fonts (Roboto, Google Sans).