GrapheneOS only works on Google phones AFAIK 🥴
Discussion
Trouble somewhere with NIP57.
You're right about the Pixel. There's good reason for this, discussed at length on the GrapheneOS website.
Also, look at which devices are supported, e.g. the Pixel 5 is where I'd start now (and what I'll probably upgrade to this year), as well tested by now... but they're keeping up with Pixel 7 if you're going straight for the bling.
💜