AlDollazSince you unlocked the bootloader you can probably use this guide to enable volte https://forum.xda-developers.com/rog-phone-2/how-to/guide-enabling-volte-vowifi-v2-t4028073 other Zenfone 6 users have said it works with TMobile
I should have done more research before buying this phone. What a mistake. Now I can't return it because I unlocked the bootloader.
That's totally my fault, but still. A device made in 2019 doesn't support VoLTE for the most popular ZF6 carrier in the US is beyond silly.