In the middle of that tablet tester log is a long run of P=24.9% and I assume that you started off with low pressure then increased it to reasonably heavy pressure as you made the stroke.
So it looks like the pressure value is being clipped to about 1/4 of what it should be by the time it gets to krita.
Does your Gaomon settings utility have any indication of the pressure output and does it show 100% when you press hard?
Is a driver update available from the Gaomon website? (I know you said it doesn’t provide much help.)
Unistalling and reintalling krita won’t change anything.
Clicking the pen pressure icon will only disable/enable pressure sensitivity. It’s enabled when you run krita for the first time.
Messing with the brush settings will only mess up the brush settings. They work fine ‘out of the box’ with the full range of pressure inputs.
In theory, it may be possible to ‘compensate’ for this using the Input Pressure Global Curve but that would be a terrible solution and would mean acccepting defeat and settling for a second class user experience.
Can you try the following:
Disable Windows Ink in the Gaomon settings, Disable Windows Ink at the Windows system level (I’m sure it can be done via the Ink icon on the system tray or some other control path).
Set krita to use Wintab, close krita and do a shutdown restart of everything.
It may work and it may not but it won’t take long to try it.