I installed arm64-current on a Lenovo x13s. The machine seems fine
except the second column of keys, like Ctrl_L-X or Ctrl_L-2 do
nothing. E.g. 'x' by itself works, Ctrl-C does too. But not
Ctrl_L-X. Neither in X11 nor in the console.

xev doesn't show any event when I hit 'x' after 'ctrl'. The situation is
a little different with Ctrl_R, only Ctrl_R-X doesn't work, but Ctrl_R-S
works. All these keys work by themselves (e.g. 'ctrl' or 'x'). It
doesn't look like a mechanical/electrical problem to me, but I could be
wrong here. Any ideas about troubleshooting this further?

Sadly, I didn't test the machine enough in windows before installing
OpenBSD. I guess spending a few hours doing that is the most expedient
debugging approach?

Thanks
Greg