So I finally found a speed extension that works superbly with customisable speeds and a great keyboard shortcut. Well done on this extention.

Custom default play speed and even custom speed increments, works with the existing youtube keyboard shortcuts.

Works pretty dang seamlessly! Love the ability to add your own custom values, but keyboard shortcuts (rather than single-increment arrows + a clumsy drop-down list, which gets cut off at the top if you have lots of individual speed values) would make this even more intuitive. What's really missing is pitch control—all the other add-ons that manipulate pitch have clunky UI or fussy functionality. Regardless, this here's the best speed control add-on I've yet to come across.

elegant and useful! special respect for the ability to create custom speeds!!!

some talk too slow in their videos, this quickly helps

Simple, elegant, and does the job.
A few improvements I can think of:
Let us use the mouse wheel on the icon of the addon to increase/decrease speed.
Let us customize the keyboard shortcuts, or disable them completely.
These aren't must-haves, but would be nice.
Still, 5-star, and thank you.

Works seamlessly on my M1 Air. Very minimal. Non intrusive. Customizable. The developer is very responsive. Let's get this guy a beer