We are well aware of certain issues which surfaced after the WordPress 5.5 update rolled out, and the fact that these issues still remain after the 5.6 and 5.7 updates came out. Namely, due to WordPress removing the jQuery migration with the new updates, some users may experience setbacks or errors when it comes to certain elements on their websites.
Luckily, there is a relatively straightforward solution for this at this time, and it works for all 5.5, 5.6 and 5.7 versions of WordPress.
https://wordpress.org/plugins/enable-jquery-migrate-helper/
After the plugin is installed and activated, the jQuery migration issue will be effectively fixed. We recommend going for this easy-to-use option, at least until the next WordPress update fixes the issue permanently.