Add speed buttons to any HTML5 <video> element. Comes with a loader for YouTube and Vimeo
< Opinie na Video Speed Buttons
I think VSB being bloated may be the reason I stopped using it years ago (which is also why it went unmaintained for so long). I'm using it now, though, so expect more updates as I get annoyed with it and fix things.
Added an experimental update. On v1.0.10, you can now select an alternate "controller" which is far more minimalistic with no loops and is keyboard-only. To enable it, go into your script and change `controller_type` to `CONTROLLER_VSC`. This will cause video speed buttons to not load at all, and instead a much smaller chunk of code will load. It's so small it fits in the second screenshot.
The controls are +/- to adjust the speed and * to reset it back to 1x.
So try it out, maybe it'll work better for you. It does things in a different and much simpler way so it's less prone to break on a long-lived youtube page. However, sites that like to fight you on the speed might still give trouble.