I have it too. The image randomly freezes or the entire playback freezes.
But also regular video (not live) has problems, for example it skips forward a few seconds at random moments.
I don't know if this is something to report on bugzilla. It's hard to report this because I would have to constantly record my screen while watching YouTube to catch the random moment when it happens.

I have uBlock and SponsorBlock. I'm on Arch Linux.

Never had any issues with that, and I'm also using ublock. Do you have any other browser add-ons installed? Any tampermonkey scripts targeting youtube or something?

Anyone else experience this? I haven’t ever had this problem with Chrome. Live streams on YouTube seem to freeze once an hour or so. Actually YouTube just seems way slower and much more laggy on FireFox. I am using uBlock Origin so maybe that is throttling things, but I’m not sure.

Any advice?

I guess you missed all the news about this last monthish?

There's been something of an ongoing battle over showing commercials versus getting around showing them, with people reporting purposely(??) added slowdowns into the player, etc.

~Anti~ ~Commercial-AI~ ~license~ ~(CC~ ~BY-NC-SA~ ~4.0)~

Could switching your user agent help? Try setting yourself to Windows+Chrome.

I have no advice, but I have a similar issue. Firefox on Windows 10 with just uBlock Origin.

YouTube works fine at first, but if I watch a lot of videos in a row then after an hour or so it starts to load slowly. Then it stutters, then finally I get audio and a single frame for the whole video. Shorts seem to accelerate the descent. I haven't tried live streams yet, but I bet I'd get the same result.

Completely closing all Firefox instances and reopening fixes it for an hour. It acts like a memory leak, but I'm not even close to maxing out my RAM when it crashes. My fans get loud which makes me wonder if it's botching the hardware acceleration.

Sadly I can't help beyond telling you you're not crazy.