Here's an old guide for obs classic that explained some of the settings:
https://obsproject.com/forum/resources/custom-parameters-of-quicksync.104/
For the recording encoder, the best rate control methods to use are in this order (if supported by the processor): LA_ICQ -> ICQ -> CQP. "Sane values" are approx 22-25 for the ICQ value, leave everything else at default. For the CQP values, same thing, though just set the same value for all three CQP values.
For streaming, just use CBR and set your bitrate as per normal.
Note that you cannot change the rate control for the stream encoder. You can only do it if you use a separate recording encoder for quicksync.
