Can confirm the high cpu usage issue a user posted below. It seems like it happens if used in combination with Zoom Page WE extension. If I disable one or the other the problem doesn't occur.

Using the Return Youtube Dislike userscript doesn't cause the issue so I'm going to use that for now instead.

This video is another one that causes problems https://www.youtube.com/watch?v=F03gEzdLa2g