Starting to believe it is a T-Mobile service issue in my area. Previously had a pixel 2 on Verizon and never had a problem. Planning to leave T-Mobile in the near future.
Phone calls sound much better than my previous carrier (some cheap mvno) and things generally Just Work.
Only complaint is that it's missing some things I hadn't realized were not stock Android, such as per-app volume control. I just might switch back to LG after this one dies, though the battery seems to be holding up much better so who knows.
Do you use wifi calling when you are at home? It has been my experience that T-Mobile WiFi calling is absolutely terrible, and I've oftentimes wondered if something in the software "locks" into WiFi instead of switching to cellular data, until the phone is rebooted.
Sometimes it'll work fine for a while after leaving and a few hours later I notice I don't have service.
I'm in the Northeast USA on T-Mobile. You?