brooke2k parent
I use youtube a worrying amount, all through firefox (and I am also an ADHD 1000 tabs open person), and I have never had this experience across multiple computers.
Youtube freezes for me on Windows with Firefox. Sometimes it freezes the whole browser so added a rule to block it in uBo and use another browser for it (which also helps me reduce my time on youtube thanks to the added friction). I don't know if its an issue with my specific hardware or what. In Mac and Linux (different PC) it works fine.
You're using an add-on that blocks core functionality. That is not Firefox's fault.
I'm blocking it to avoid it freezing the browser. Before I blocked it, it froze the browser.
You need to keep the same youtube tab open and navigate the website a considerable amount on it for it to occur. I use the same tabs repeatedly, and by the end of the day I get an incredibly sluggish site. Not the end of the world, since I just close the tab and start a new one, but it does exist.
Firefox has had documented issues with youtube for the better part of a decade at least.