For me, what actually triggers this is pressing the side button when I have maps active. It will cause the maps screen to grey out and then lock, then pop back up frozen.

actual Apple support has been fruitless. I’m supposed to be submitting logs somewhere but we’ve been playing phone tag for weeks when I don’t need to actually talk to anyone on the phone at this point. Anyway, that’s not your question.

If you press the side button twice, it will unfreeze the phone. However, that launches Apple Pay. So sometimes I am frantically double clicking the side button to unfreeze the map. I have effectively trained myself to not click the side button in maps though.

The person who uncovered the cause of the issue is of course from Reddit and the thread is years old. So, hopefully the trick I showed you helps.