Nicknameforgotten
Doing a bit of investigating shows that OnePlus offers Co-Branding on their phones.
The website shows the Hasselblad, Cyberpunk, Genshin, McLaren, JCC+ (Jean-Charles de Castelbajac), COLETTE, and JBL OnePlus co-branded phones.
I have a feeling my next phone will be a GrapheneOS - OnePlus co-branded phone.
(Scrolling 3/4 of the way down this page shows OnePlus' Co-Branding section)
The reviews on OnePlus phones are generally quite good.
I would be interested to read others' thoughts on this.