Nothing we can do about your lock screen password. How about removing the lock screen password and have no lock screen security and then see what happens when you try to access Firefox passwords.

Yes, with locks reen disabled I can access passwords. However, with no lockscreen password, fingerprint and facial unlock for the whole phone is also disabled

Right, the issues appears to be the phone. Turn your security back on like it was before and see what happens. On my Sony Xperia, I get the phone unlock code prompt, put in the code and then I can access my Mozilla account passwords.