www.kimovil.com/en/…/fairphone-5

Fairphone 5 will support all of T Mobile’s 4g bands, but only half of the 5g bands. This means that it will have lower 5g coverage than a US phone, but it will have as much 4g coverage as any US phone using t mobile. Based on your use cases, I don’t think there will be too many problems if your phone doesn’t get 5g speeds. Remember that most ppl didn’t have 5g just 3-4 years ago and people were able to do everything that you’re planning on doing with 4g networks.

If you are going to look into alternative OSes, consider degoogled androids over linux phones as you seem to need some android specific apps. Most degoogled androids have the ability to install Google apps with something called microg. For voice assistants, you might be able to install Google voice using microg or choose an open source voice assistant like this one: github.com/PoCInnovation/Elivia-AI. I don’t use voice assistants much, so I’m not too sure how well those work.