2) Please disable the AMP plugin and then check back to your site after clearing the browser cache.
If still, you think the issue persists then please take the complete backup of your site and remain all the third-party plugins deactivated on your site as well and share the site WP Admin and FTP Login Credentials with us in a private content area of this topic so that we will check it for you.
Note: We also need your permission to debug your site as well which includes deactivating all the third-party plugins and on-site Customization as well.
Please take the complete backup of your site as well before providing the requested info.
