I was just thinking about this after seeing your post. Quick question before I give my full two cents, are you planning on doing any streaming or heavy video editing on this rig, or is it strictly for gaming? That 4090 is a beast at 4K, but your workflow makes a huge difference in which CPU makes sense. If you want the absolute top-of-the-stack for productivity and gaming, the AMD Ryzen 9 7950X3D 16-Core 32-Thread Processor is incredible, though it can be a bit of a pain to set up with core parking so the right cores handle the game. Then there is the AMD Ryzen 9 7900X3D 12-Core 24-Thread Processor, but honestly, it feels like a weird middle ground because only 6 of its cores have access to the 3D V-Cache. Tbh, for most people, those extra cores just sit idle during Cyberpunk sessions anyway. What kind of other apps are you planning to run?

Honestly, if you want to be practical about your budget, you could look at the AMD Ryzen 9 7900X 12-Core Processor. Since you are playing at 4K, the GPU is doing almost all the work, and the performance gap between the high-end chips becomes tiny. I always prefer saving some cash where it doesnt hurt the actual gaming experience, and the non-X3D chips are very mature and reliable now. My main tip would be to focus on stability. A 4090 is power-hungry, so make sure you have something like the Corsair RM1000x 1000W Power Supply. Also, definitely stick with G.Skill Flare X5 32GB DDR5-6000 CL30 memory. Getting that 6000MHz speed is the sweet spot for AM5 stability right now. Pushing for faster RAM is kinda risky and often leads to system crashes... keep it simple and reliable.

I'd play it safe with the AMD Ryzen 7 7800X3D 8-Core 16-Thread Processor. It's more reliable since you wont deal with scheduling issues, and at 4K, extra cores dont really help gaming performance anyway.