Keep Your XMR Private: What is a DeGoogled Phone? (video)
Using Monero on a device with a spyware operating system defeats the point. Let's learn the basics of rejecting Google's surveillance and some different alternative Android operating systems:
https://video.simplifiedprivacy.com/what-is-a-degoogled-phone/
Yes it should be OEM unlocked. In theory sandboxed google play on graphene should not be able to access it. But if you use real cell service with a SIM card, then the IMEI number (by default) can be seen by the carrier.