How to detect unauthorized mdm or monitoring on my device iPhone SE 3rd generation

Password are exposed, can’t add my card to apple wallet, browser issues I’m constantly giving false errors and then get blocked bc it says I try to much. I logged in after erasing my devices but ran across a sign in apple account that’s all it said and would not let me sign out. I’m getting told everything with is weird and they haven’t seen it happen going to the Apple Store I was apple to use a test phone and use my card for Apple Pay but my phone says card issuer contact them.. I could on on and on but prefer to talk