Here’s a possible solution to reduce network noise with your internet connection:
https://www.smallgreencomputer.com/collections/systemoptique/products/opticalmodule-deluxe
The components you’d need would cost just over $700.
For a PC card, this might work:
Pink Faun is out of stock on their USB bridge cards. The link above is for a PC bridge with various coax outputs. Might not be what you’re looking for.
I can’t vouch for any of these products, personally. But, you should be able to find plenty of reviews for them. Some of the folks who post here use Small Green Computer products, perhaps they'll chime in here.
Also, if you look in the digital forum, there are some very good threads on reducing network noise.