DDR5 6000 CL30 or CL28.
At Amazon, Newegg.
ROG Strix X870E-E is fit your budget.
@node_o Expensive.
Ryzen 7 5700X3D.
For overclocking 9950X3D, consider Arctic Liquid Freezer III 420. This CPU hits thermal limits before power limits, so superior cooling is essential.