Comment 73 for bug 1946368

To make life easier, on the problem Ubuntu machine, I installed ssh server:
   sudo apt install openssh-server
and left an open ssh connection to it from another RPi.
When the Ubuntu machine display froze, the OS itself was still running, and from other machine, I unlocked the Ubuntu lockup with
   sudo service gdm restart
I don't like rebooting a machine by cutting power for ... reasons.
I've not tried the s/kms/fkms trick yet, but I am doing daily updates. I'm also getting a lot up uptime between freezes.