Hi,
I love my fairphone 4 but if there is one drawback I found is that the vibrations are too weak.
I come from a fairphone 2 where it was (too) strong but at least I never missed a call.
Today I have to turn on ringtones and constantly have to play with volume up/down to match my environment which is cumbersome.
My FP2 was always on vibration mode it was really cool to know if something was important without having any music/sound.
Even placed on my desk, It is hard to tell if the phone is vibrating: the room should be quite silent.