Hmm, the log unfortunately has no real error that explains the black screen :/
Could you try adding an image source or text source and see if that renders correctly when you start a preview?
One idea, for the blackscreen problem, would be checking that you are on up to date drivers for your graphics card. But definitely check my idea with the image/text source as well.
Apart of that I saw two small things you should probably change, first of all you entered crf=x into the custom x264 commandos section. You have to change that X to a number. I would recommend 15 as a good starting point.
Then you currently have your Microphone selected for both Desktop and Mic input. So you probably want to go to the Advanced settings and uncheck "Use Input device for desktop audio" option. That should give you game/desktop sound on stream.
Oh, last but not least you have activated the "Use Mic QPC timestamps" option, also in the advanced section. You normally only do this if you have sync problems, so you might wanna deactivate that as well.