[OptionOfT]

I had a related issue.

I had an iPhone, then work offered iPhones, and I (stupidly) did not separate the phones or the accounts. So personal stuff on work phone. It's Apple, It's supposed to be good. MDM removal should completely remove work stuff from the image right?

Well, not so much. I had a non-removeable TMobileWingman WiFi network (even though I moved to Verizon) configuration, a stuck VPN configuration and a couple of shortcuts that I couldn't remove.

Eventually I fixed it by taking a backup, going through it with iMaze, and basically try to nuke stuff, and then restore the backup, hoping it work.

Quite insane how much stuff is left around in your iPhone backup by the way.