I have Opera installed on Ubuntu via the snap.
I had to re-install Opera from scratch. It is still the same computer, OS installation, and GNOME keychain, etc., but nevertheless just copying over the 'Login Data' database from the backup of /snap/opera is not working.
The passwords are verified in the Login Data SqlLite DB but Opera doesn't show them in the Password Manager, probably because decryption is not working. Is there something else needed from the old data directory to make the decryption work?
The only change I can note is the Opera snap version has moved up from 371 to 374, but that's really minor, and even on an 'Upgrade Startup' from the backup, it still doesn't accept the passwords.