Greasy Fork is available in English.
Moves the video description to the right of the video, adds options for smaller video, retro player, retro style, and more
< Youtube - Right Side Descriptionについてのフィードバック
This is not designed for mobile platforms for multiple reasons. I expect you can't access the settings as you need to hover over the header. Did the default settings at least seem to work? If they did, I could make the settings panel available but I can't provide any fixes for mobile-exclusive bugs that you may encounter.
You should now be able to access the settings button. I can't provide support for bugs on mobile but hopefully it will work okay.
Not working here. Kiwi browser + tampermonkey and desktop view.