I have the same problem in version 1.83.118 on Windows 11,
It happens on every video and it blocks saying there is some unexpected error.
I tried to turn off the shield and all worked as it should be and when i turned the shield on again Youtube was slow at start but now it works all fine, i guess it’s a Youtube error when it tries to load an Ad in the video (not sure)
This fixed itself while I was adding this comment and checking videos in old tabs!
For me, the problem didn’t start immediately after the upgrade, and youtube tabs which I had opened prior to this issue were playing as normal. It looks to be all fine now though.