This is 100% anecdotal of course, but I’ve noticed weirdly inconsistent behaviour. I have one tab I permanently keep open for YouTube and that one loads videos really fast. If I open a second tab by following a link from that main tab, then it partly loads the site and sits there for a weirdly long time before any content even appears.

I’ve got a really fast connection too, and nothing else was having issues. This whole thing is bizarre.