Yes, I have an Apple Developer account and it is the first time that I create a Mac Package.
I have try several times , to be sure to follow the institution of the have the right Developer ID application, that's why there are lots of certificats.
Unfortunately, we cannot revoke then the olds Developer ID application.
I have also certificat for iOS APP Smarphone, these work fine.
I am not sure for the process that Apple asks to me for the first time :
"If you're generating your first Developer ID certificate, the software that you sign it with must be notarized by Apple in order to run on macOS 10.14.5 or later. Learn how to submit your software for notarization"
Maybe this could be the problem?