Your best bet for now is to buy a new Pixel direct from Google, or a used one from eBay that the seller advertises as already having GrapheneOS on it (or otherwise guarantees that the bootloader is unlockable). These ones are worth a lot more than the ones that can only run Google/carrier Android.
https://grapheneos.org/install/web#prerequisites
I own two GrapheneOS Pixel 7 units, which should get any Google blob security updates (which GrapheneOS incorporates) through October 2027, and GrapheneOS may still support it with source updates after that. So in a year or so, I might get the GrapheneOS Motorola if it's available, or a later Pixel. (I never buy these new, since I don't want to carry a several hundred dollar phone when a 2 gen old one is still great, thanks to GrapheneOS.)
I also did the math and determined buying a new unlocked phone outright on this plan was far cheaper than paying Verizon monthly for one.
Currently running my Pixel on Warp (Verizon) with zero practical difference, and starting Monday I'll also have a backup iPhone with a small $8/mo Darkstar line. The money I've saved since switching more or less paid for the iPhone, and I'll be getting 2x reliability for way less ongoing cost. The better app/website/support and extra features are just a bonus.
On any plan.
There’s a reason that as soon as you walk into a cell store they immediately try to schmooze you into signing contracts and leasing phones.
It’s the way they make the most margin!
