Boomba Hi there.
Here are the devices that GrapheneOS supports:
For more devices to be supported, they need to meet specific criteria, which are currently not met by other devices:
It may be possible for you to build GrapheneOS for other devices, but they won't retain all of the security properties as a lot of it relies on the hardware (hence why GrapheneOS supported devices are chosen very carefully), and it also wouldn't really be called GrapheneOS. It would be an unofficial fork.
I hope that helps, even though it's probably not really what you wanted to hear.