There’s a lot of basic things that can be done to help a PC generate less noise. Neat best practice wiring, using SSD drives instead of mechanical drives, not using fans (passive cooling) and a GOOD quality power supply. Seasonic is known for making good low ripple power supplies. In the OS and Bios you can also turn off or disable hardware you’re not using, com ports, hardware, BT and the likes.
Then there’s stuff like this. https://forum.sonusapparatus.com/t/sotm-thread-sms-200ultra-neo-tx-usbultra-snh-10g-tx-usbhub/1103/2?u=db_cooper