I have tried regular as well as the developer version of Firefox, but no matter what I use, YouTube videos always skip frames after every 10-15 seconds or so. So I use Brave for YouTube and other WebGL heavy stuff and Firefox developer version for daily browsing.
That sounds very strange. Certainly don't see that in Firefox on Mac (work laptop) and both Linux and Windows (personal laptop). Try adding the h.264 extension. That forces YouTube to provide h.264 videos which is hardware accelerated on pretty much any hardware.
