I use optimal setting with great results. I think this is best because having it on max performance just makes the card run at full throttle even when it doesn’t need it. On older cards this would result in a more noticeable performance increase but newer cards are better at regulating themselves. Personally, having tested the optimal mode and prefer maximum performance modes with 3DMark I have found that on my 3080, it makes zero difference. However, the maximum performance makes the card idle hotter and the fans run louder when they don’t need to.
If I may ask, why do you limit your fps? Clearly your card can do more if it’s throttling down, so why would you not want a couple extra frames?