Im still trying to collect more info on the fans. There are 3 types of fans that can be replaced:
Jugu used these fans in his:
CPU Cooler: 70mm amazon.com/Silent-FN-SX07-22-D…ling-Screws/dp/B00BF3UJKC
Power Supply: 40mmx20mm amazon.com/Scythe-Mini-ULTRA-Silent-SY124020L/dp/B000VRVHFO
My CPU was a bit whineeeeeey, whereas my PSU fans was pure jet aircraft +10000dB
Replaced with aforementioned recommendations and I can now hear what's going on, on screen.
The case fan is still pretty loud, but it's a pure air-flow noise, and tbh it could be disconnected without issues if only played for short/moderate sessions. I'd say my GPU fan is by far the noisiest component now.
Thanks for the recommendations Cell & Jugu