amdgpu linux drivers are baked into the kernel for the general use case, and the 7800XT (being relatively new) requires kernel 6.3 or newer, whereas right now Debian 12 (bookworm) currently supports 6.1 out of the box. You will also want non-free-firmware for the various pieces of hardware that don’t release an open source firmware (including GPUs).
My opinion is that you would be better off with a distro that uses a newer kernel by default (Ubuntu 23, Fedora 38, Arch, etc), rather than trying to force Debian to use a newer kernel. Distro opinions tend to come off strong, but you choose what makes you happy.
Congrats on the new hardware, and best of luck!