I have PC also for gaming and it is very loud for gaming. My PS4 Pro is not loud (bought it in 2018).
But no problem, it's always nice to be called a liar when I say the truth. Thank you.
If you have a PC that is very loud and that is what you are comparing your PS4 to, it very well could sound quiet to you (I would look into that, cause that must be one loud PC).
Compared to any other console however, it sounds like a jet engine. I got my PS4 Pro after God of War was released, so not an old model. Has always been noisy as hell. Same with my launch PS4 and a later model that I got for my son as well. The only other console that is similar would be the 360, which also sounded like a jet. My X1 and Switch are both near silent, and my PS3 to this day is quieter as well.
I an just pointing out that all evidence I have seen as well as the vast majority of PS4 owners out there it seems are claiming the PS4, PS4 slim, and PS4 Pro are loud as heck compared to other consoles. Do with that info what you will, but if all you can compare you Pro to is a loud PC I can see why you might not realize the issue.