Answers for "how to speed up youtube videos faster than 2x"

speed up youtube videos more than 2x

Windows: Ctrl + Shift + J
macOS: Command + Option + J

Copy and paste this into the console:
document.getElementsByTagName("video")[0].playbackRate = x

Replace x with the speed you want the video to be played at, and enter/return.
Works for speeds with decimals too, so you can try 3, 0.1, 200, etc.
Cheers!

more than 2x speed on youtube

Ctrl+Shift+J
document.getElementsByTagName("video")[0].playbackRate = x