Dmf943 I'm not sure you understand how this works. It's not possible with devices that are end-of-life, no longer receive firmware or driver security updates, and receive extended support from GrapheneOS via a legacy branch based on Android 13 (4a) and 14 (4a 5G) with only the Android Open Source Project security backports, certain other security patches, and other minimal changes to keep them working. You can't just simply "trick" an old device to use features that are only supported on newer devices...
https://grapheneos.org/faq#device-support