burger menu accessibility

try this in child-theme functions.php:

function custom_replace_burger_anchor_with_button( $items, $args ){ 
    $pattern = '/(<li[^>]*class="[^"]*av-burger-menu-main[^"]*"[^>]*>)\s*<a([^>]*)>/is';
    $items = preg_replace($pattern, '$1<button type="button" $2>', $items);
    $items = preg_replace('/<\/a>(\s*<\/li>\s*$)/', '</button>$1', $items);
    return $items;
}
add_filter( 'wp_nav_menu_items', 'custom_replace_burger_anchor_with_button', 9999, 2 );

BUT: Please note that in this case, you will no longer need to assign all styles to the a tag, but rather to the button tag.
In this case, it might be better to use role=”button” and class=avia-button.

function custom_enhance_burger_anchor_regex( $items, $args ) {
    $pattern = '/<a href="#" aria-label="(.*?)"/i';
    $replacement = '<a href="#" role="button" class="avia-button" aria-label="$1"';  
    $items = preg_replace($pattern, $replacement, $items);
    return $items;
}
add_filter( 'wp_nav_menu_items', 'custom_enhance_burger_anchor_regex', 9999, 2 );

No CSS break: Since it remains an anchor-tag, all Enfold styles for the menu continue to work perfectly.
A11y-compliant: With role=”button,” we tell the screen reader: “Ignore that there is a link here; treat this element like a button.”

maybe it is better to not add the class avia-button because it might come into conflict with some stylings.
use a different class there f.e.: avia-burger-button
then you can easily select it via this class.