Same issue, also on Orion 0.99.121-beta (WebKit 614.1.20) and MacOS 13.0. It looks like the YouTube interface changed a little bit between yesterday and this morning when the issue began.
Going on YouTube.com is fine, as soon as I launch a video (for example youtube.com/watch?v=l1MC27f3Lew that was in my suggestions on the home page) my CPU gets saturated and the temps go to 70ยบ+
As soon as I close the window playing, everything goes back to normal
Tried the same on Firefox 106.0.3 and Safari without issue