Youtube has bizarre lag spikes

I've noticed this with youtube on PC exclusively but video will sometimes stutter every few seconds for a moment but it happens so often to make it unplayable. Sometimes closing and re-opening fixes it, other times you'll have to just check in on it later. Loading up the main page or any list of videos is fine but actual playback becomes incredibly slow.

I thought it might be lag associated with adblock but even after removing any extensions with adblock or VPNs, I still experience it. It isn't an internet speed issue because everything else runs perfectly fine and youtube on the mobile app doesn't have this issue at all.

It's been like this for months now and it has to be some sort of issue on Youtube's end but I cannot figure out what it is.