Thanks to my mate @edk from IRC I learned of the compose key. I configured my KDE Plasma desktop to use Right Alt as my compose key in System Settings -> Input Devices -> Keyboard -> Advanced. Then I updated the firmware and deployed a .XCompose file that I generated, and now I have a symbol keyboard on my Debian Linux workstation!
So I upgraded my Ubuntu from 20.04 to 22.04. That mostly went without problem but there are still a few gremlins to iron out. One change was some of the desktop widgets I was using in the previous version seem to have been replaced. I found the replacements easily enough. I particularly like the new CPU activity widget, it’s a much more sensible way to visualise 24 CPU cores than the previous widget which just gave one reading instead of 24.
