motorola one 5g Ace

I had an issue with service on this phone as well. The issue was 5G coverage in my area. It was blazing fast at the store but the rest of the city it goes in and out, often causing apps to hang or pages not to load. It seemed to prefer using terrible spotty 5G.

The solution for me was to go into Settings > Network & Internet > Mobile Network > Preferred Network Type, and change this from "5G On" to "LTE/3G/2G". 

This disables 5G. In my area LTE coverage is great so I no longer deal with interruptions. It's a terrible solution but the problem is either T-Mobile's coverage or some hardware issue with the phone so this is the best solution for now. Either way, LTE is as fast as most people Cable internet. It'll handle YouTube at 1080p and anything else pretty well, so I'm happy. Wait until T-mo is done beta testing their 5G.