adding aria-labels to lightbox arrows/controls

It depends a little on how you want to use it. If you only want to change this to “next bio” and “previous bio” for certain custom classes, we would need to rewrite this code a little.

f.e. if you have a gallery – then you can give a custom class to that gallery element (f.e. team-member)

function add_magnific_popup_aria_labels() {
    ?>
    <script type="text/javascript">
    (function($) {
        'use strict';
        
        if (typeof $.avia_utilities !== 'undefined' && typeof $.avia_utilities.av_popup !== 'undefined') {
            
            var originalOpenCallback = $.avia_utilities.av_popup.callbacks.open;
            
            $.avia_utilities.av_popup.callbacks.open = function() {
                
                if (typeof originalOpenCallback === 'function') {
                    originalOpenCallback.call(this);
                }
                
                var self = this;
                
                setTimeout(function() {
                    // Determine labels based on the gallery container
                    var prevLabel = 'Previous image';
                    var nextLabel = 'Next image';
                    var closeLabel = 'Close lightbox';
                    
                    // Check if the clicked element (currItem.el) is inside a container with a custom class
                    if (self.currItem && self.currItem.el) {
                        var $link = $(self.currItem.el);
                        
                        // Find the parent lightbox container element
                        var $lightboxContainer = $link.closest('.avia-gallery, .av-masonry, .av-horizontal-gallery');
                        
                        if ($lightboxContainer.hasClass('team-member')) {
                            prevLabel = 'Previous person';
                            nextLabel = 'Next person';
                            closeLabel = 'Close biography';
                        } else if ($lightboxContainer.hasClass('products-gallery')) {
                            prevLabel = 'Previous product';
                            nextLabel = 'Next product';
                            closeLabel = 'Close product gallery';
                        } else if ($lightboxContainer.hasClass('projects-gallery')) {
                            prevLabel = 'Previous project';
                            nextLabel = 'Next project';
                            closeLabel = 'Close project gallery';
                        }
                        // Add more conditions as needed
                    }
                    
                    $('.mfp-arrow-left').attr('aria-label', prevLabel);
                    $('.mfp-arrow-right').attr('aria-label', nextLabel);
                    $('.mfp-close').attr('aria-label', closeLabel);
                }, 50);
            };
            
            var originalChangeCallback = $.avia_utilities.av_popup.callbacks.change;
            
            $.avia_utilities.av_popup.callbacks.change = function() {
                
                if (typeof originalChangeCallback === 'function') {
                    originalChangeCallback.call(this);
                }
                
                var self = this;
                
                // Update labels when changing images
                var prevLabel = 'Previous image';
                var nextLabel = 'Next image';
                
                if (self.currItem && self.currItem.el) {
                    var $link = $(self.currItem.el);
                    var $lightboxContainer = $link.closest('.avia-gallery, .av-masonry, .isotope, .av-horizontal-gallery');
                    
                    if ($lightboxContainer.hasClass('team-member')) {
                        prevLabel = 'Previous person';
                        nextLabel = 'Next person';
                    } else if ($lightboxContainer.hasClass('products-gallery')) {
                        prevLabel = 'Previous product';
                        nextLabel = 'Next product';
                    } else if ($lightboxContainer.hasClass('projects-gallery')) {
                        prevLabel = 'Previous project';
                        nextLabel = 'Next project';
                    }
                }
                
                $('.mfp-arrow-left').attr('aria-label', prevLabel);
                $('.mfp-arrow-right').attr('aria-label', nextLabel);
            };
        }
        
    })(jQuery);
    </script>
    <?php
}
add_action('wp_footer', 'add_magnific_popup_aria_labels', 999);

you see this line includes masonry etc. if you like:

// Find the parent lightbox container element
var $lightboxContainer = $link.closest('.avia-gallery, .av-masonry, .av-horizontal-gallery');

or even better – just use the team-member element as it is and parse a popup by your own.
see with snippet on that example page: https://webers-testseite.de/teammember-vitae-2/
PS: It is always best to examine each individual case closely, as this is the only way to offer a customized solution. Otherwise, one indulges in speculation.

The last solution has the advantage that you only use the pure Enfold element for team members and then create your own lightbox with it. Disadvantage: you would have to rebuild your page and discard our previous design. In the window on the right side of the page, you can see that only plain text is entered in the Description Input Fiele — the Lightbox retrieves the image, name, and position from the existing DOM elements.
To change the aria-label – just edit these lines:

tPrev: 'Previous Biography',
tNext: 'Next Biography',