How to customize the author page?

sadly the filter avf_post_slider_args is not implemented in the author archive.
It is ruled by author.php and loop-author.php.

So we have to built a custom loop-author.php.

here is my loop-author.php on pastebin:
see: https://pastebin.com/2vuxUhSH
download: https://pastebin.com/dl/2vuxUhSH

put it inside your child-theme/includes folder.
– now you have a filter to rule the layout:

add_filter( 'avf_author_loop_args', function( $atts, $context ) {
    if( $context == 'author' ) {
        $atts['type']         = 'grid';  
        $atts['columns']      = 4;               // columns count (bei grid)
        $atts['preview_mode'] = 'custom';        // 'auto' oder 'custom'
        $atts['image_size']   = 'gallery';       // 'portfolio', 'gallery', 'square', etc.
        $atts['contents']     = 'excerpt_read_more'; // 'excerpt', 'excerpt_read_more', 'title', 'content'
    }
    return $atts;
}, 10, 2);

and for styling to quick css:

#top.author .av-author-grid-container {
  display: grid !important;
  gap: 20px;
  margin: 40px 0;
}

/* Standard: 4 Spalten */
#top.author .av-author-grid-container {
  grid-template-columns: repeat(4, 1fr);
}

/* Dynamisch per Filter */
#top.author .av-author-grid-container.av-columns-2 {
  grid-template-columns: repeat(2, 1fr);
}

#top.author .av-author-grid-container.av-columns-3 {
  grid-template-columns: repeat(3, 1fr);
}

#top.author .av-author-grid-container.av-columns-5 {
  grid-template-columns: repeat(5, 1fr);
}

/* Responsive */
@media (max-width: 989px) {
  #top.author .av-author-grid-container {
    grid-template-columns: repeat(2, 1fr) !important;
  }
}

@media (max-width: 767px) {
  #top.author .av-author-grid-container {
    grid-template-columns: 1fr !important;
  }
}

see: https://webers-testseite.de/author/guenni007/

the column count inside that snippet is added as custom-class – so we can react on it by css setting.