Certain key combinations are not working
Solution 1:
To assess whether the keyboard is failing, you could use any application to monitor key presses. See options here, here, here:
screenkeysudo evtestxev
You can perform further evaluations by:
- Booting from a Live USB and/or Windows. If the problem stems from your Ubuntu configuration, these should work.
- Using another keyboard in your Ubuntu.
All this should suffice to give a clear answer.
Related
- https://wiki.ubuntu.com/LaptopTesting/Keycodes
- https://manpages.ubuntu.com/manpages/focal/man1/showkey.1.html