Is his connection ADSL on old phone lines, is it an old or new area.
Sounds like or could be “noise” on the line. Have you asked your ISP to test for “noise”. Problems in infrastructure do develop that won’t show on a speed test.
Is the server close? Your last speed test was less then 50 miles with a hi ping of 44ms. Were is the game server.
You have not given a description of your ISP connection. You have mentioned wireless and nics. Is your connection Cable, ADSL over copper, wireless ???
How do you connect to your router if you have one? Ethernet on twisted pair, USB, WiFi ? What is the extent of your LAN in you house are you sharing the connection?
You say you even lose the TS connection ?? Is the Server set to “host all” (set g_bServerHostAll 1)
Get you line checked for noise by whoever owns then (telco)