DeArrow is great! The difference is that this extension automatically replaces thumbnails for all videos, whereas DeArrow is limited to ones submitted by the community.
It’s worse, since DeArrow benefits from its community to get actually relevant thumbnails.
I've actually never even heard of this kind of tool. I hate all of news crap that appears in my youtube feed. Sometimes I even fall for it and click. Installing this.
and DeArrow even does titles. OP should maybe have looked for existing things in the problem-space?