In a bid to reduce global electronic waste, Fairphone has created a smartphone that owners can repair themselves. What makes its technology so sustainable?
I do not consider any smartphone sustainable, including Fairphone.
The hardware is repairable but that’s rarely the issue. Most phones are being thrown away because the software is obsolete and non-upgradable. IIRC, Apple supports their phones with updates for ~7 years, and Fairphone for ~5 years. OTOH, PostmarketOS works on Fairphone, so hackers can self-support for longer. But the stock OS is Android which is officially supported for less time than iOS on Apples.
If you want to live a sustainable lifestyle, either keep using a 10—15+ year old Android and live with the obsolescence and limitations, or just don’t bother with a smartphone.