The taxonomy category is assigned to post type post by default, so if you assign category to a CPT, there will be two CPTs connected to that taxonomy. And you will need to modify the query in the archive template to display two (or more) CPTs on the archive page. Just like
You need to add the code to the file archive template in the theme/child theme folder, for example archive.php. If you are not familiar with coding, you can create a service request here https://metabox.io/contact/, our development team will help you with an extra fee.