Youtube and other video players only allow you to listen to 2x speed max. But your brain can handle more. After a while you will get used to faster and faster speeds. It is useful in certain situations.
Create a folder in your bookmarks bar, called "v"
Create a bookmark with the name 3x and give it this url
javascript:document.querySelector('video').playbackRate=3
Do the same for all the speed steps you want, i recommend going from 1 to 3.5 in 0.25 increment steps, that way your brain can get used to higher and higher speeds.
Create a bookmark called pip with this url
javascript:((function()%7B%5Bdocument%2C...%5B...document.querySelectorAll(%22iframe%22)%5D.map(iframe%20%3D%3E%20iframe.contentDocument).filter(iframe%20%3D%3E%20!!iframe)%5D.some(d%20%3D%3E%5B...d.querySelectorAll(%22video%22)%5D.filter(video%20%3D%3E%20video.paused%20%3D%3D%20false%20%26%26%20video.ended%20%3D%3D%20false).some(video%20%3D%3E%20!!video.requestPictureInPicture().catch(err%20%3D%3E%20console.log(err))))%7D)())
This will allow you to have a small "picture in picture" for the vide you are viewing. (Although if you want to change the speed while showing picture-in-picture, you have to be in the tab that has the video element)
(I found the pip snippet on the internet somewhere sometime)