Forcing me to recite my PIN every few weeks is one of the most irritating UX I’ve seen.
I’m sure there’s some smart engineer explanation in terms of cryptography and being unable to recover it if lost. But just let me disable it if I’m okay losing my entire account if I forget it.
Also last time I checked the binding of a phone number to Signal was really bad. I had a friend abandon Signal and I could never sms them ever again.