You are showing log from your streaming PC.
So, we need to check what you produce with your gaming PC:
21:40:37.424: video device: AVerMedia HD Capture C985 Bus 1
21:40:37.424: video path: \\?\pci#ven_1af2&dev_a001&subsys_a0011af2&rev_00#4&3227f04d&0&00d8#{65e8773d-8f56-11d0-a3b9-00a0c9223196}\{957bd672-7934-4b55-b81a-3e22b14c679a}
21:40:37.424: resolution: 1440x900
you are capturing 1440x900.
Then you upscale to 1920x1080 canvas and stream this (or 1280x720 rescaling)
So, if your first PC produces 1440x900, set your canvas to 1440x900 in second PC
Do not rescale.
Your stream will have two black dars at both sides.
You can avoid these bars using 1600x900 canvas and stretching a bit all.