AMD Ryzen 7000 vs 9000 isn’t a huge difference iirc, mostly more efficient. The X3D variants are definitely worth it for gaming performance though, so I’d wait for the 9000 X3D reviews to compare.
32GBs is plenty of RAM for now, 64GB is overkill for gaming purposes. I don’t use 100% of my RAM ever and that’s with Discord and a bunch of browser tabs open while playing Cyberpunk or heavily modded Minecraft.
For the GPU, I currently use a 7900 XTX and haven’t had issues running that with Manjaro Linux. Haven’t used an Nvidia GPU with Linux, but from what I can tell their support was/is dubious but improving.
All I want is a Vivaldi based on Firefox