First off... yes, there are things to be done like update windows so that you can turn off game mode, and pare down game capture sources.
BUT
The issue is with network connection. That's it -- let's keep the focus there. 61% frames dropped in test #1, 1.5% dropped in test #2. Bitrate of 2500kbps.
You say you have issues after 2 hours. What router do you have? What ISP do you have, and what kind of upload speed should you have?