Seems that we can play with vibration levels (durations) in /usr/share/ngfd/plugins.d/50-droid-vibrator.ini (Gigaser GS5 )or similar, depending of the phone model. (XA2 has both 50-droid-vibrator.ini and 60-droid-vibrator.ini )
A change on the GS5 made the kb vibra feedback work again as well as menu vibrations (was set too short to be felt) after a reboot.
The setting corresponding to the keyboard keypresses is touch_weak.
It would be easier not having to reboot to test the vibration duration but I don’t know what service t restart.
Any idea?
Edit: strangely, the fix stops working after typing some text typing/some time. No more vibrator. However, the modifications are still in the file. I have a hardware problem. When I hit the phone, it vibrates again. The mod in the above file was necessary and is working.