I have similar problem. It pretty much started when 2 free months of my yt premium run out(about 2weeks ago). Opera run ok earlier, now it hangs from time to time making one tab with the video nonresponsive, it seems to happen more often whenever I move opera window to my 2nd monitor. It either plays the video or hangs, there is no in between that hangs after some time, unless it happens in exact moment opera app window crosses to 2nd monitor.
For now I can play everything on yt while using MS Edge, it had none of the issues above.
