Gallery metabox doesn´t show new images / save changes since Wordpress 6.0

I use the code below to display images in posts. It basically works, but changes made via "Add Image" are no longer saved since WP 6.0 or 6.1.

The manual variant via the "post_banner_image" field below by entering the image ID still works.

here a front-end screenshot

<?php 

// Add Meta Box to post
add_action( 'add_meta_boxes', 'multi_media_uploader_meta_box' );

function multi_media_uploader_meta_box() {
    add_meta_box( 'my-post-box', 'Media Field', 'multi_media_uploader_meta_box_func', 'post', 'normal', 'high' );
}

function multi_media_uploader_meta_box_func($post) {
    $banner_img = get_post_meta($post->ID,'post_banner_img', true);
    ?>
    <style type="text/css">
        .multi-upload-medias ul li .delete-img { position: absolute; right: 3px; top: 2px; background: aliceblue; border-radius: 50%; cursor: pointer; font-size: 14px; line-height: 20px; color: red; }
        .multi-upload-medias ul li { width: 120px; display: inline-block; vertical-align: middle; margin: 5px; position: relative; }
        .multi-upload-medias ul li img { width: 100%; }
    </style>

    <table cellspacing="10" cellpadding="10">
        <tr>
            <td>Banner Image</td>
            <td>
                <?php echo multi_media_uploader_field( 'post_banner_img', $banner_img ); ?>
            </td>
        </tr>
    </table>

    <script type="text/javascript">
        jQuery(function($) {

            $('body').on('click', '.wc_multi_upload_image_button', function(e) {
                e.preventDefault();

                var button = $(this),
                custom_uploader = wp.media({
                    title: 'Insert image',
                    button: { text: 'Use this image' },
                    multiple: true 
                }).on('select', function() {
                    var attech_ids = '';
                    attachments
                    var attachments = custom_uploader.state().get('selection'),
                    attachment_ids = new Array(),
                    i = 0;
                    attachments.each(function(attachment) {
                        attachment_ids[i] = attachment['id'];
                        attech_ids += ',' + attachment['id'];
                        if (attachment.attributes.type == 'image') {
                            $(button).siblings('ul').append('<li data-attechment-id="' + attachment['id'] + '"><a href="' + attachment.attributes.url + '" target="_blank"><img class="true_pre_image" src="' + attachment.attributes.url + '" /></a><i class=" dashicons dashicons-no delete-img"></i></li>');
                        } else {
                            $(button).siblings('ul').append('<li data-attechment-id="' + attachment['id'] + '"><a href="' + attachment.attributes.url + '" target="_blank"><img class="true_pre_image" src="' + attachment.attributes.icon + '" /></a><i class=" dashicons dashicons-no delete-img"></i></li>');
                        }

                        i++;
                    });

                    var ids = $(button).siblings('.attechments-ids').attr('value');
                    if (ids) {
                        var ids = ids + attech_ids;
                        $(button).siblings('.attechments-ids').attr('value', ids);
                    } else {
                        $(button).siblings('.attechments-ids').attr('value', attachment_ids);
                    }
                    $(button).siblings('.wc_multi_remove_image_button').show();
                })
                .open();
            });

            $('body').on('click', '.wc_multi_remove_image_button', function() {
                $(this).hide().prev().val('').prev().addClass('button').html('Add Media');
                $(this).parent().find('ul').empty();
                return false;
            });

        });

        jQuery(document).ready(function() {
            jQuery(document).on('click', '.multi-upload-medias ul li i.delete-img', function() {
                var ids = [];
                var this_c = jQuery(this);
                jQuery(this).parent().remove();
                jQuery('.multi-upload-medias ul li').each(function() {
                    ids.push(jQuery(this).attr('data-attechment-id'));
                });
                jQuery('.multi-upload-medias').find('input[type="hidden"]').attr('value', ids);
            });
        })
    </script>

    <?php
}


function multi_media_uploader_field($name, $value = '') {
    $image = '">Add Media';
    $image_str = '';
    $image_size = 'full';
    $display = 'none';
    $value = explode(',', $value);

    if (!empty($value)) {
        foreach ($value as $values) {
            if ($image_attributes = wp_get_attachment_image_src($values, $image_size)) {
                $image_str .= '<li data-attechment-id=' . $values . '><a href="' . $image_attributes[0] . '" target="_blank"><img src="' . $image_attributes[0] . '" /></a><i class="dashicons dashicons-no delete-img"></i></li>';
            }
        }

    }

    if($image_str){
        $display = 'inline-block';
    }

    return '<div class="multi-upload-medias"><ul>' . $image_str . '</ul><a href="#" class="wc_multi_upload_image_button button' . $image . '</a><input type="hidden" class="attechments-ids ' . $name . '" name="' . $name . '" id="' . $name . '" value="' . esc_attr(implode(',', $value)) . '" /><a href="#" class="wc_multi_remove_image_button button" style="display:inline-block;display:' . $display . '">Remove media</a></div>';
}

// Save Meta Box values.
add_action( 'save_post', 'wc_meta_box_save' );

function wc_meta_box_save( $post_id ) {
    if( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) {
        return; 
    }

    if( !current_user_can( 'edit_post' ) ){
        return; 
    }
    
    if( isset( $_POST['post_banner_img'] ) ){
        update_post_meta( $post_id, 'post_banner_img', $_POST['post_banner_img'] );
    }
}


?>

Can someone help me to get the other part working again?

current_user_can('edit_post') is no longer valid in WordPress 6.1. Here's the relevant core trac ticket.

You must now use one of these formats:

current_user_can( 'edit_posts' );
current_user_can( 'edit_post', $post->ID );
current_user_can( 'edit_post_meta', $post->ID, $meta_key );