The pinephone hardware feels like a prototype due to the old A20 cpu (heat problems, poor battery life).
The lesser-known SHIFT6mq has an actual mobile chip and apparently works correctly as a phone under postmarketOS (only GPS, NFC and Camera missing): https://wiki.postmarketos.org/wiki/SHIFT_SHIFT6mq_(shift-axo.... There are pointers on the wiki to hack on the camera if you want to help the cause.
The lesser-known SHIFT6mq has an actual mobile chip and apparently works correctly as a phone under postmarketOS (only GPS, NFC and Camera missing): https://wiki.postmarketos.org/wiki/SHIFT_SHIFT6mq_(shift-axo.... There are pointers on the wiki to hack on the camera if you want to help the cause.
The Fairphone 5 is another good candidate for hacking: calls and camera are not working: https://wiki.postmarketos.org/wiki/Fairphone_5_(fairphone-fp...