I turned on debug. It looks like a conflict with LayerSlider or Enfold. Again, this works fine in PHP 7.4. I just get this with PHP 8.1.
Fatal error: Uncaught TypeError: Unsupported operand types: string + int in /home/account/sub.staging.domain.com/wp-content/themes/enfold/config-templatebuilder/avia-shortcodes/slideshow_layerslider/slideshow_layerslider.php:153 Stack trace: #0 /home/account/sub.staging.domain.com/wp-content/themes/enfold/config-templatebuilder/avia-template-builder/php/class-shortcode-template.php(1332): avia_sc_layerslider->shortcode_handler(Array, ”, ‘av_layerslider’, Array) #1 /home/account/sub.staging.domain.com/wp-includes/shortcodes.php(433): aviaShortcodeTemplate->shortcode_handler_prepare(Array, ”, ‘av_layerslider’) #2 [internal function]: do_shortcode_tag(Array) #3 /home/account/sub.staging.domain.com/wp-includes/shortcodes.php(273): preg_replace_callback(‘/\[(\[?)(email|…’, ‘do_shortcode_ta…’, ‘[av_layerslider…’) #4 /home/account/sub.staging.domain.com/wp-includes/class-wp-hook.php(324): do_shortcode(‘[av_layerslider…’) #5 /home/account/sub.staging.domain.com/wp-includes/plugin.php(205): WP_Hook->apply_filters(‘[av_layerslider…’, Array) #6 /home/account/sub.staging.domain.com/wp-content/themes/enfold/template-builder.php(102): apply_filters(‘the_content’, ‘[av_layerslider…’) #7 /home/account/sub.staging.domain.com/wp-includes/template-loader.php(106): include(‘/home/account…’) #8 /home/account/sub.staging.domain.com/wp-blog-header.php(19): require_once(‘/home/account…’) #9 /home/account/sub.staging.domain.com/index.php(17): require(‘/home/account…’) #10 {main} thrown in /home/account/sub.staging.domain.com/wp-content/themes/enfold/config-templatebuilder/avia-shortcodes/slideshow_layerslider/slideshow_layerslider.php on line 153