Try an Ubuntu dist-upgrade with Nvidia drivers installed and report back.
It’s a bit of cheating because Ubuntu supports dist-upgrade only if you use nothing but universe. Granted it might work still but if it doesn’t your paid support will just tell you to restore a backup and try with universe packages only. At least that’s what I heard. But it’s been long since I used Ubuntu and maybe the situation is better nowadays. Back then, this screwed be over big time.