A single Zen5 core can do 32 single precision FMAs per clock.

That's using SIMD, but so is Nvidia for all intents and purposes. Those "cuda cores" aren't truly independent: when their execution diverges, masking is used pretty much like you'd do in CPU SIMD.

A lot of the control logic is per-SM or perhaps per-SIMD unit -- there are multiple of those per SM. You could perhaps make a case that it's the individual SIMDs which correspond to CPU cores (that makes the flops line up even more closely). It depends on what the goal of the comparison is.