OnePlus has released multiple updates to Android 10 on non TMobile varient One Plus 7 Pro devices. I've reached out to them to find out why i cannot update my phone and was told TMobile has to approve the software first. It's been out for a while now and I would like to get the update in a timely manner. Why can't I get the update now when it's been out for over a month.
OnePlus hasn't finished testing the Android 10 update for the T-Mobile version as of yet. With the merger going on between Sprint and T-Mobile, I wouldn't be surprised if a part of the delay is waiting for updated carrier aggregation from T-Mobile for them to add in. The versions of Android 10 for the 7 Pro and 7T might be released and even called stable, but they are by no means finished or polished builds. Have some patience! You don't want a bug filled broken update pushed to your device, but just in case you do. Go sign up for the FUT program on the OnePlus forum.
Manage your T-Mobile account