I'm not an expert but....
00:52:15.355: CPU Name: Intel(R) Core(TM) i5-7200U CPU @ 2.50GHz
00:52:15.355: CPU Speed: 2712MHz
00:52:15.355: Physical Cores: 2, Logical Cores: 4
00:52:15.355: Physical Memory: 8060MB Total, 3645MB Free
00:52:15.355: Windows Version: 10.0 Build 14393 (revision: 693; 64-bit)
Depending on what you're streaming, that is unlikely to be powerful enough to anything above 720 if you're streaming a USB capture card. Indeed when I had a similar set up, I was down to 640 sometimes lower. This was the advice I got:
Looking at your log that dual core CPU is just not going to cut it, when using a USB capture card. and at that lower resolution, even using Ultra fast preset is just not enough. You could try lowering your Elgato's Input resolution to 1280x720. though you then would need to set whatever console you are using to also 720p. It could help a little.
So it depends on what you mean by "best quality settings".