Add a bookmarklet. You add a bookmark, and then you replace the URL with one of these:
Interactive variable-rate:
javascript:void%20function(){document.querySelector(%22video%22).playbackRate=parseFloat(prompt(%22Set%20the%20playback rate%22))}();
One-click (I have half a dozen of these):
javascript:void%20function(){document.querySelector(%22video%22).playbackRate=2.7}();
These work on any non-iframe HTML5 video player. I'm pretty sure you can edit to work on audio too, but that's less frequently useful. I guess this version of the code only works on the first video in a page; that has never limited me, but it's easy to fix by changing to `querySelectorAll` and using a `.map` (or `.forEach`) with anonymous function. The bookmarklet technique doesn't work on iframes (like embedded players often are), but only because of browser security restrictions, so if you open the dev console (ctrl-shift-i), you can choose from
1) just load the iframe itself, or
2) run the JS code yourself in the browser console, where the browser's security rules don't stop you
If you're an even modestly competent web developer, you can solve novel UX problems on any website you use moderately often, or in this case UX problems with HTML elements that appear on many many websites.
I agree with the grandparent poster. I watch nearly everything at 1.5x to 3x speed (anything where the timing/tempo isn't itself part of the subject matter). Perhaps I should up my game and go for the "3x-6x" GP claims, because still some content is just too damn slow. Basically the clearer the enunciation of the speaker, the faster you can watch it. Pause and rewind as necessary (e.g. on YT it's space to pause and left arrow to back up 5 seconds).