One caveat--you have to be certain that you get a Pixel with an unlocked bootloader. There are a lot of Pixels (mostly sold by Verizon) that are unlocked for use with any carrier, but whose bootloaders remain locked. If you have one of these ex-Verizon phones, there is no way as of now to unlock the bootloader.
There's no way to easily tell that those phones have unlocked bootloaders, though. Ex-Verizon phones may be completely carrier unlocked, will work on any network, and still have locked bootloaders. This isn't an issue for anyone running stock Android, but will restrict those phones from being used to run GrapheneOS.
