I tried to switch for a Nokia dumb phone a while back and I got burned by buying one that didn't support the right bands (definitely no LTE). It got borderline unusable service and I had to give it up.

Next phone I get will probably be a dumb phone, but it's just something to be wary about for other potential buyers. If anyone has good resources on understanding this stuff, I'd love it. Otherwise I'll have to write it up when I learn next time. It feels like it's hard to get good info on.