

Does it work if you unplug and replug?
In general, yes.
If you hit a button other than power does it wake up, or does it say “no signal” or something?
Yes.
Does the laptop see it?
I’m assuming not as it does not display on it. Next time it happens I’ll see what xrandr says.
Anything in any log?
Nothing in Xorg.0.log and nothing that seems related in the journal. I’ll keep journalctl --follow running and see if anything that I didn’t pick as being related comes up next time it happens.
Can you force a redetection from the laptop?
Probably, but I don’t know how.
I’ve been using various versions of keepass for ever. Until recently I had the database on Google drive. It’s now local and sync’d with syncthing. It’s a bit “different”, but once you get used to it, it works very well.