How to delete App (files with cross sign) that cant delete from Application on Mac
The prohibitory symbol means the application will not run on your machine.

I'd recommend either user128733 or CousinCocaine approach as seen here:

How to remove an icon from launchpad that does not appear in the Finder?

Application cleaner tend to be OK.  FYI: General mac cleaners are to be avoided.

https://nektony.com/how-to/delete-apps-from-launchpad