We try an external USB keyboard as well as a boot to safe mode or a boot to another OS. It does sound like a bad keyboard but more testing is required.
A month or so ago, certain key combinations have stopped working. What I have found so far is
left ctrl a
left ctrl z
left ctrl x
right shift z
To be clear, for example, right ctrl a works find. And left ctrl everything else not listed works fine.
I am up to date on windows update and have run MalwareBytes. I have restarted in safe mode, but the problem persists.
Windows 10 Home 1909 build 18363.535
Asus laptop TP41OU