You're right..I too have the 1+7P currently still but today imma upgrade to the 8T on T-Mobile...the updates was lacking on the 7P, I never knew how to update it to the global version (not a tech guy lol) currently running on Android 10 with Oct security patch
So I go to the xda forum... download the 3 files...place the 3 files in one file..connect my phone..then proceed to press "start" and let it do it's own thing ? 🤔
Just was reading about the new 5G McClaren 7T device and it comes with Android 10 out the box, my only question is when is Android 10 coming to the 7T Pro phone, I feel T-Mobile been slacking on the updates for the OnePlus devices