i tested it again :
there was the topic of mine here: https://kriesi.at/support/topic/transition-speed-in-slider-alb/
that on fading the images – the fade effect from last to first image on looping was with its default transition speed.
so there was a fix for slideshow.js on : https://kriesi.at/support/topic/transition-speed-in-slider-alb/#post-1219428
that was not perfect but much better than before.
But when inserting your changings in that fixed file – the fading from last to first image is as before : wrong.

activate Enfold Parent : then export theme settings file.
then activate Child : import theme settings file.

if you look into : functions.php file of parent enfold you see on line 174ff:

Click to enlarge

you see there is a filter: avf_modify_thumb_size which we can use to add or modify the thumbnails.
you see that there are on some crop rules on the otheres not

you can redefine such an existing size via that filter f.e:

/***** redefine existing size  ****/
function modified_thumb_for_blog_pages( $size ){
  $size['entry_with_sidebar'] = array('width'=>900, 'height'=>450 );      
  return $size;
}
add_filter('avf_modify_thumb_size', 'modified_thumb_for_blog_pages', 10, 1 );

i think for single blog posts the “entry_with_sidebar” is taken.
If you have no sidebar on the blog – clear – the entry_without_sidebar is taken.
BUT: you will not see directly an effect. You had to regenerate the tumbnails ( see comment on functions.php )

If you like to preserve that transparency header on start replace with:

/****** responsive case when burger is visible *************/
@media only screen and (max-width: 989px) {
  .responsive #top #wrap_all #header .container {
    width: 90%;
    max-width: 90%;
  }
   
  #header {
    position: fixed !important;
    height: 80px !important;
    max-height: 80px !important;
  }
  
  .responsive.html_mobile_menu_tablet #top #wrap_all .av_header_transparency {
    background-color: transparent;
    color: #000000;
    border-color: #f2f2f2;
  }
   
  .responsive #top .av-logo-container ,
  .responsive #top .logo a,
  .responsive #top .logo img {
    height: 80px !important;
    max-height: 80px !important;
  }
  
  .responsive #top .av-main-nav .menu-item-avia-special a {
    height: 80px !important;
    line-height: 80px !important;
  }
}

this for your child-theme functions.php:
Change if clause to your needs.

function custom_burger_menu_active( $active, $context ){
  if( is_page(3) ) {
    return true;
  }
  return $active;
}
add_filter('avf_burger_menu_active', 'custom_burger_menu_active', 10, 2 );

or do you mean: different menu items in the hamburger menu of a specific page ?

So if you can manage this – I would recommend that you don’t activate any other caching tool (or Enfold Merging).

See the whole tutorial on: https://www.siteground.com/tutorials/wordpress/sg-optimizer/

But that maybe the issue: https://www.siteground.com/tutorials/wordpress/sg-optimizer/supercacher/

maybe this helps you : https://wpshout.com/quick-guides/how-to-clear-your-siteground-cache/

Caches are a great performance benefit for your site, but them getting “stale” or outdated is a bit bummer. Fortunately, it’s simple to clear the SiteGround cache of your WordPress website, and you’ll get into a rhythm with it quickly. Here’s a video guide …

• Press the “Purge SG Cache” button in your top admin bar. If you don’t see this button, you’ll need to install the SG Optimizer plugin. (You should also contact SiteGround support to make sure that you’ve actually enabled its caching layers.)
• To make sure the resources aren’t still being cached by your browser, hard-refresh your browser. You do this with Ctrl+Shift+R on Windows or Cmd+Shift+R on a Mac.

Look again at my article before, we seem to have posted it here almost simultaneously.

But you do not have a caching tool like W3TC or Total Cache running.
Not that we would leave out something so mundane in the search for solutions. Because they just save static pages to be able to deliver them faster.

With Enfold under the Performance Tab, did you turn the merging on? ( File Compression )

I recommend – as long as you are working on the site – to disable this merging completely. Merging does provide better performance, but it is a hindrance for this very reason.
Below these settings you will find the switch : “Delete old CSS and JS files?” which should also be set to on.

These merged files will stay there until you save them with the setting “Delete old CSS and JS files? These files are usually used for rendering your page.

of course this does not explain why content is also delayed.

by the way – dear mods: how can i use this only for a specific page ?

Guess that this is just an image – a photoshop thing.
Do you need this often – or just for a few images?

See here – this is made with caption of Image ALB:
https://webers-testseite.de/image-with-ribbon/

In any case I think it would be better to do it in a photo editing program. Just look at the way it behaves when you make the screen smaller.

the image alb got a custom-class: with-ribbon

.with-ribbon .av-caption-image-overlay-bg {
    display: none;
}

.with-ribbon .av-image-caption-overlay-center p {
  background-color: rgba(255,0,0,0.8);
  color: #fff;
  text-shadow: 1px 2px 3px #000;
  padding: 20px ;
  position: absolute;
  top:5%;
  left: -10%;
  transform: rotate(-30deg) ;
  width: 80%;
  text-align: left;
  text-indent: 40px;
  box-shadow: 1px 2px 8px #000;
  font-size: 36px;
  text-transform: uppercase;
}

When I install a new theme, I always look directly at how to install the corresponding child theme. With Enfold this is very easy. There is a pre-built one, which you just have to upload via ftp.
An existing Enfold installation that you have already set up can easily be converted to a child theme.
I think that the advantages of a child-theme outweigh the few disadvantages of a parent-theme only installation.

If you need help, let me know.

i guess you can follow this answer here:
https://kriesi.at/support/topic/change-h3-tags-in-footer-widget-child-theme-of-enfold/#post-727939 and from Yigit here:
https://kriesi.at/support/topic/change-h3-tags-in-footer-widget-child-theme-of-enfold/#post-728320

On register-widget-area.php you find the names and ID’s of the widget areas. I cannot see a Forum Widget Area – but you will know that on your installation. ( i let it on section instead of your div – then all would be the same syntax – if you like change section to div)
The normal blog widget is called: Sidebar Blog with id: av_blog
for child-theme functions.php:

function ava_remove_some_widgets(){
	unregister_sidebar( 'av_forum' );

	register_sidebar(array(
		'name' => 'Forum',
		'before_widget' => '<section id="%1$s" class="widget clearfix %2$s">',
		'after_widget' => '<span class="seperator extralight-border"></span></section>',
		'before_title' => '<h4 class="widgettitle">',
		'after_title' => '</h4>',
		'id'=>'av_forum'
	));
}
add_action( 'widgets_init', 'ava_remove_some_widgets', 11 );

For the font size change, couldn’t find the relevant CSS selectors either.

For advice, I would have to see the page it concerns.

_____________________
Off Topic
as long as the headings should be all the same tag i would take this code instead of Yigits – a little bit shorter:
for child-theme functions.php:

function register_custom_footer_widget(){   
    $footer_columns = avia_get_option( 'footer_columns', '5' );
    for ($i = 1; $i <= $footer_columns; $i++){
    unregister_sidebar( 'av_footer_'.$i );

    register_sidebar(array(
      'name' => 'Footer - column'.$i,
      'before_widget' => '<section id="%1$s" class="widget clearfix %2$s">', 
      'after_widget' => '<span class="seperator extralight-border"></span></section>', 
      'before_title' => '<h5 class="widgettitle">', 
      'after_title' => '</h5>', 
      'id'=>'av_footer_'.$i
    ));
  } 
}
add_action( 'widgets_init', 'register_custom_footer_widget', 11 );

yes loop-index.php is to edit. But i guess you would need to have a whole child-theme file for that. It is not as simple as on the title link.

there are a lot of styling possibilities on the blog post ( elegant, business, modern-business ) and blog-layouts and image dimension options – so no way to do it only with one function.

there are sometimes links on an icon : line253 with class: post-author-format-type this link should also be canceled?

this is so far my effort – but without removing that link above.
See here: https://pastebin.com/nbD71qZi
Download here: Link

This icon is not allways present – but on modern-business it is.
And on blog-view there is the author link. : https://webers-testseite.de/pureinstall/category/allgemein/

Child-theme loop-index.php : download the above and create the same folder tree structure as in parent theme
means: create an includes folder in child-theme and put the loop-index.php into it.

Try – and tell me if it works for you.

ok – if even the link to that page is not public then you had to wait.