Question about case noise normalized thermal testing applicability if you change the fans

Nothing here about linus and steve, just a question I am hoping more knowledgeable PC part people can help me answer, and since the question is directly about GN testing this sub seemed more appropriate than buildapc.

Looking at cases for a new build, and was planning to buy a case without fans or replace the fans that come with it with Noctua Ax14s (side note, if you know fans that cool even quieter, let me know. These are just the best I know of so far). I'm looking to maximize cooling as much as I can without my computer getting loud enough to bother people in the same room.

At first I thought GN's noise normalized tests would be a perfect place to start. However, I am not sure if the GN's tests are representative of how the case would perform in this scenario - is it showing the impact of the case or really just of the out of the box fans? The antec flux pro performs great and the Hyte Y60 does not so well, but the flux comes with 4 140mm fans and 2 120s compared to the Hyte's 3 120mms.

I am not criticizing the methods at all, it is great to have data on this and no doubt stock fan configuration is really important given the number of people who will just run with it. I just want to gauge people's thoughts on how much we can extrapolate from these tests. Side note 2, if anyone has replaced the fans on a Flux pro or North XL and has comments on how quiet they can get, let me know.