I'll have to learn how to look back at the logs. For years everything was fine and stable so I didn't get into the tech much.
For the past month the whole system has been going crazy every few days. The CPU would go to 137% for over an hour and nothing was accessible. The cloudron-support --troubleshoot would slowly show everything was ok, with an added 'fgets: Connection reset by peer'. Everything would eventually come back to life.
I keep hoping an update from an app or Ubuntu would fix it. Next time it happens I'll check top/htop live.
Now updated to 5.11.82