The specific issue the OP mentioned (of verification information being persistent in the in app chat) has been discussed elsewhere but the upshot was when Monzo replaces intercom with in house software they’ll look to have special “verification” chat items that can be triggered by COPs, and which aren’t persistent.
With regards to phone/app security: at the moment, to do any “action” in app you need your PIN. I understand people might want more security but not less, ie pin to open app - I don’t, that would ruin the smooth experience for me. Maybe it should be optional?
I do not understand those with no/pattern based authentication moaning about app security - secure your phone first!