Add multiple custom meta boxes to different custom post types

The add_meta_box() functions 4th parameter is where you add your CPT’s for the backend.

$post_type
(string) (required) The type of Write screen on which to show the edit screen section ('post', 'page', 'dashboard', 'link', 'attachment' or 'custom_post_type' where custom_post_type is the custom post type slug)

You should be able to add an array for multiple CPT’s using the 4th parameter.

For the front end you would use the conditional tag in a custom function or template file depending on how you want to output.

is_singular('your-cpt')

Or

is_post_type_archive('your-cpt')