kitty Please read the FAQ :
https://grapheneos.org/faq#supported-devices
https://grapheneos.org/faq#recommended-devices
https://grapheneos.org/faq#future-devices
GrapheneOS is a project that focuses on hardening security and privacy on mobile, it's very different from projects like LineageOS which focuses only on the adoption of a maximum bunch of devices, often at the end of their life cycle, and not on security and privacy, for now, only Google's Pixels meet the hardware security standards that are essential for GrapheneOS to function properly, GrapheneOS cannot support unsecured mobile devices.
As GrapheneOS is open-source, it may nevertheless be possible to build it on an unsupported device, you'll get your own version of GrapheneOS and not the official GrapheneOS version, and it can't be considered GrapheneOS.
https://grapheneos.org/build