Gmod (Extremely) Slows My Internet

A lot of the time when I try to play Gmod (14.04.19), my internet goes to crap. More specifically, when I look at the server list it becomes so slow that it’s unusable. This happens even more often when I try to refresh the server list. When it gets slow like this and I try to connect to a server, it says connection failed after 4 retries. My internet stays this way for a while, even after quitting Gmod, so I’m not sure why that’s happening.

My normal internet speed is 20 mbps down and 10-ish mbps up.
I have done a scan with Malwarebytes, if that’s important, so I’m pretty sure it’s not a virus I have.

Anyone else experiencing this? Or anyone have any ideas to help?

Does it happen with any other Source games?

I haven’t noticed it with other Source games, might check tomorrow if I remember.

I can actually confirm this. This is one of many HTML server browser problems.

Do you know of any way to fix it?

There is a setting in steam to change the rate at which servers are polled, decrease that, and try using the classic server browser in Garry’s Mod