GrapheneOS is finally ready to break free from Pixels, and it may never look back
(www.androidauthority.com)
Nothing is pretty much a Chinese OEM...
The phone is fully designed, engineered, tested, built, and firmware written in China... Pei just has his marketing office in the UK so he can claim it as a UK company. Maybe they give some aesthetic design direction in the UK too. Pei has a history of lying to make his companies seem like something they aren't.
(Though they did have a couple of software job postings up recently, so maybe they are trying to slowly change that and do some of the software in the UK)