pedanticmouse
Re:T-Mobile begins blocking iPhone users from enabling iCloud Private ...
on Monday January 10, 2022 @06:07PM (#29884318)
It looks like T-Mobile isn't actually preventing or blocking Private Relay, but that it doesn't function while T-Mo's Content Filtering is enabled. Here's more information on that.
https://tmo.report/2022/01/t-mobile-blocking-icloud-private-...
tl;dr - disable T-Mo Content Filtering on your account and PR will work just fine