Is YouTube not slow for you on Firefox? Both my windows pc and Linux PC have super slow buffering on YouTube lately with Firefox. On mobile it’s fine, somehow. Nothing seems to help. And it’s not my Internet, everything else is normal speed except YouTube.
Edit: using User Agent Switcher and pretending to be Chrome worked immediately. This is definitely YouTube fucking with Firefox users again. They must be doing A/B/etc group testing which is why not every Firefox user is experiencing it, but many are if you go to the Firefox tech support threads.