OP. This is not the answer to the question that you asked, but it is the answer to the problem you want resolved...
Option 1:
Put the PC in another room, and buy a 20m fibre optic hdmi cable, a 20m usb3 cable and a 4-port powered USB hub.... I used this solution when I was running my old system; a 5930k overclocked to within an inch of it's life... It sounded like an aircraft taking off when gaming... But with the PC upstairs in the spare room, and the cables running downstairs to the living room, it was absolutely silent!... In BIOS, I set "wake on USB keyboard" so that I could just press any key on the keyboard downstairs to start the PC, and didn't have to run upstairs every time I wanted to use it XD.
You can pick up the cables on Amazon when they come on offer: The fibre optic hdmi cable was the most expensive at like £40 on Amazon... The USB cable - £20... The hub; £18.
Total Cost: £78 ...
If you can get away with 10m cable length, it's obviously a bit cheaper... I needed 20m, and probably would've got 20m anyway for compatability when moving home (which I have now, and although my PC in my gaming room upstairs is silent now, I also have the cables running to the living room too, so I can chill down there on the PC too.)
Otion 2:
1) You need a case... just sitting it in a wood surround with open front and rear, but closed top, you will get some stagnancy of airflow... That solid wood shape also acts as a sound guide to direct any and all sound outwards towards the front and rear (where it bounces off the wall and comes forward adding to the front again!)
A cheap cheap mesh fronted case with good airflow: Kolink Citadel. About £50 in the UK.
2) A cheap cheap but high performing air cooler with much greater capacity than your actual CPU wattage: Thermalright PS120SE (about £45 in the UK) or PA120SE (as low as £35 in the UK) CPU tower cooler.
3) Put the case on the floor so that the noise isn't right next to your ear when sitting at the desk... I'm pretty sure that noise levels are something like inversely proportional to the square of the distance, so the further you can get it from your ear, the quieter it will appear, very rapidly. Also, if your floor is carpeted, it will absorb sound instead of reflecting it like solid wood case and desk... If your floor isnt carpeted, buy a small carpet door-mat and put it on it!
Build instructions:
The case comes with 2x 120mm fans... scrap those out for some 140mm fans (Be Quiet or Noctua or Arctic F14 (cheapest at £10 each) or the like) at the front AS EXHAUST... 140mm fans can run slower and quieter than 120mm fans for the same airflow!.. Potentially, maybe, put one of the 120mm fans provided in the rear as intake. Fit the PS120SE air cooler as intake rear, exhaust front. Set all the fan speeds to minimal, juuuust running speed (you really will only need very low speed on all the fans, which will be virtually silent). If you can, undervolt your CPU (curve optimiser in BIOS for AMD), to reduce it's power consumption, and therefore the heat you have to dispel. Intake rear gets cool air stright to your CPU tower cooler so it can run lower fanspeed for the same cooling, and setting the front fans as exhaust moves the leading edge of the fan blades away from the mesh, which reduces turbulence and noise.
This setup will be silent, for all intents and purposes.
Total Cost: £115-£125 (including 140mm fans)
I built a 12700k and 3080ti for my mate a year or two ago in this very case. At idle or browsing the web it is absolutely silent... Gaming, it's so quiet that it is on the very very edge of hearing if you actually listen for it.
My own silent system is in an SFF NR200 case, 12700k and 3080 10G (both undervolted and watercooled), with custom loop water cooling, dual radiator (240mm slim radiator in the top, and 280mm radiator in the bottom) with the watercooled GPU vertical between the two... At idle, the fans are at 25% and it is silent at 29C on both the CPU and GPU with 19C ambient. Gaming, it has fans at 40%, which is virtually silent, 67C max on CPU and/or GPU... 45% fans, I can juuuuust hear, at 62C max... Waterpump at 40% for all these tests so that that too is silent. (I'm running noctua fans and ended up having to do a noctua fan mod on the power supply because that was all that I could hear from the PC when gaming, and it proper peed me off!)
Case: £65
Fans: £140
Slim 240mm Rad: £65
Arctic Freezer 280mm AIO: £80 (I cut the tubes off it, and inserted the other components into it's loop to make my custom loop, and refilled it with EK premix coolant)
Alphacool reservoir tube and fittings: £130+ (I can't actually remember; this is an estimate)
EK premix coolant: £15
Front and rear GPU water blocks: £360
Gelid Extreme Thermal Pads: £90
Thermal Grizzly Kryonaut Paste: £20
Total Cost: £965 ... Not a cheap solution as you requested... Damn I spent a lot for a silent gaming PC?!... Didn't really pay attention at the time, but DAMN!
