Solved! Buzzing noise when playing games

[Ineedhelpplss]

I build my first PC and it booted on the first try However, the happiness didn't last long because there was a constant buzzing noise from my monitor speakers whenever I started playing a game. The sound comes from the PC and transfers it to the monitors but I'm not sure where exactly the sound is coming from. I'm using the 3.5mm cable.
There are no audio problems when I'm on YT or watching series.

What I tried:

• Installed the latest audio and chipset driver
• Changed the Settings in Realtek Audio Manager to 16Bit 48000Hz (Default was 24Bit 48000Hz)
• Used another PCIe slot for the graphics card
• tried the front audio input & headphones
• routed the audio and video cable seperately
• both PC and monitor are in the same electrical circuit

Are there more things I could try without spending money?

I'm going to buy a new cable and a current filter and if that's not working,I'm gonna try a soundcard or return stuff.

Thanks in advance

My build is:
Ryzen 7 1700
Asus Prime X370 Pro
16GB Corsair RAM
Red Devil Radeon RX 580
Corsair CX550M

 

[hang-the-9]

Playing a game, is this one game you tried that has the issue or all games?

 

[Ineedhelpplss]

All games I've played have this issue

 

[Ineedhelpplss]

A new cable didn't work

 

[Professor Feathers]

Check all grounds. Is everything plugged into same outlet? Maybe check in box for wires near fan. See If moving or jiggling them changes the hum w/ the game playing. Is the controller the culprit? Just basic stuff is all I got.