A small tip for adjustment.
If possible, first try to effectively eliminate interference from the power supply, for amateur use of the PC it is important not to be afraid to experiment and eliminate interference from the board's power supply and block (at least try to block) all auxiliary sources on the motherboard. (DC-DC converters around the processor are the biggest source of interference).
Adjustments and additions to blocking capacitors take some time, but they do not completely eliminate interference from the PC. However, they help significantly in preventing generated interference from penetrating into the power supply.
The PC power supply itself almost always needs to be gradually filtered, it is very helpful to double up and add another gutted filtering component from an older power supply to all DC voltages and use several times larger filtering capacities. This prevents interference from the power supply from penetrating into the motherboard, but also vice versa, from the motherboard to the power supply!
Network filtering is best done by routing the 220 V power supply into the PC case from the source and adding a large filtering component (there is no space in the source itself) because the filtering component can sometimes take up to 50% of the volume of the source itself.
What seems simple is not so cheap.
A quality network filtering component itself costs about the price of a cheap PC power supply (e.g., Schaffner FN2080-6-06).
I use these filtering components practically everywhere, even in power supplies for TRX.
(diamond GSV 3000, Astron) as supplementary, they prevent the intrusion of RF interference not only into the network but also from the network!

These modifications can achieve an improvement in the radiation of the PC itself, but all cables leading to the monitor, mouse, and keyboard must also be considered; if filtering is not possible and using ferrites or winding loops does not help, these wires must be uncompromisingly replaced with shielded ones.

Filtering PCs as a significant source of interference in a ham shack is a topic for an entire article; the biggest problem with PCs themselves is the fact that they contain a huge number of components that cause interference and influence each other. Since this is consumer electronics, filtering is very complicated because manufacturers usually focus on price rather than quality due to the very rapid obsolescence of these components.
The case itself, if well-made, absorbs up to 50% of the interference.

A little gem to conclude..
I was frustrated by interference in the network and could not find the source of interference in the lower bands of HF (160-40m). In the end, it was caused by a counterfeit original NOKIA charger that contained a single transistor and had no filtering. The interference was emitted into the electrical wiring in the apartment, and it acted like an antenna. In the meantime, I was filtering everything, including MW tubes and the electronics of the DVB-T tuner.
73!