Microsoft has fixed a bug that was causing the Microsoft Edge browser to crash while watching YouTube videos or reading comments. Microsoft Edge would become unresponsive when watching a full-screen video, and a circular loading graphic would appear. Users who experienced this issue noticed that one of their Microsoft Edge processes would begin to use gigabytes of memory, which eventually led it to crash. On Friday, Microsoft released Microsoft Edge 90.0.818.62 to the Stable branch and fixed the YouTube problem.
Source: https://www.bleepingcomputer.com/news/microsoft/microsoft-edge-update-fixes-youtube-crashes-freezes/