Same here. I thought it was just me and something to do with the increased pressure on domestic broadband due to the coronavirus. I'm using Chrome on a Windows 10 PC.
I think I've said this before but I can't help but wonder if their MP4 files do not use the 'Fast Start' option for internet streaming.
No wonder why videos take like 20 years to load.
It's definitely on the server side. It is slow as hell on my iPad too.