Update: current smartphone fell onto concrete, screen cracked, going back to using my trusty MP02 as my primary device https://www.punkt.ch/en/products/mp02-4g-mobile-phone/

I wish Fairphone was available, and worked, on US networks https://www.fairphone.com/

This phone is conceptually similar to frame.work laptops - repairable and upgradable

What is the difference between US networks and networks in Europe/Asia? 

I know that Chinese phones are blocked in the US.

Each network has approved devices. Example here's what works on AT&T

Sapiens qui prospicit - Wannabe Polymath. Interested in art, music, history, philosophy and religion.

Each network has approved devices. Example here's what works on AT&T https://www.att.com/scmsassets/support/wireless/devices-working-on-att-network.pdf

Interesting, I thought that there is an international standard for network chips.