I had a look at OnePlus and checked wikipedia to know which country it comes from, and... wow :

* benchmark results faked by software

* personal data collection

* backdoor

All of these do not appear on the English page so there's a link to the French one : https://fr.wikipedia.org/wiki/OnePlus#Controverses

Yep..... I'm not endorsing them per se, I'm just saying work is going on to get them to work on pmOS (and Mobian).