My FP4 was affected by the “ghost touch” hardware bug, i ended up getting a replacement screen after contacting support. (it never fully went away, it has a few spasms every once in a while)
also the crashing while connected to 5G put me in a few pickles. sometimes when receiving a call while watching youtube the call’s notification bubble will take up to 5 seconds to appear at all.
it seems to also ocasionally forget that it has a SIM card installed, though that sim has been in use for 10+ years, so i can’t say if that’s the Fairphones’s fault.