9900X3D and 9950X3D only make sense if you do productivity work like encoding, non-GPU related. Intensive tasks. Outside of that they serve no benefit for gaming.
As a matter of fact, the 9950X3D uses more power in a low state than a 9800X3D does at max.
7950X3D is sort of for gaming is inferior to a 7800X3D, something to do with cache layout, core optimizations, etc.. Won't pretend I know details, only that's it's not better for gaming.
7800X3D if you're on a budget which your obviously not asking about the 9900X3D or the 9800X3D. Both are basically neck to neck at gaming but the 9800 has more thermal headroom and a overall better chip.