This is the third one I've tried, and the first one that will actually block the new autoplay on a YouTube channel home page. It's not perfect (the red frame ends up above the channel home page autoplay video, instead of around it), but at least it works.

(Were these YouTube people born in a barn? What were they thinking? Finding ways to bypass browser settings and force autoplay? Don't they have better things to do? Don't they have the slightest understanding of netiquette?)