If you have the hardware for it, the best sim racing headsets are currently considered to be the HP Reverb G1, HP Reverb G2, Pimax 8K X, and Varjo Aero. None of them are currently listed as being supported, but most every one is fairly certain that they'll be compatible since they all run SteamVR.
How much power you need for any of those, is more than currently exists. Can you run sims with maxed frame rates with existing hardware? Sure, but there are always compromises, even if it's just super sampling. That said, high end CPU & GPU's will give you an incredible experience with good graphical fidelity. If you have lower end hardware, then you might want to consider a lower end headset such as the Quest 2 or Index.