5090 Secured! Need CPU Advice for Local LLMs vs. 9950X3D/9800X3D

I finally got a win and the GPU gods smiled upon me! I finally scored a 5090 FE at MSRP after what felt like forever.

Now the fun part - building a whole new rig for it. The main things I'll be doing are Gaming at 4k and tinkering with local LLMs.

I'm a bit stuck on the CPU though. Should I splurge on the Ryzen 9 9950X3D, or will the 9800X3D be good enough? Especially wondering about the impact on local LLM performance.