A Microsoft Edge bug is causing the browser to become unresponsive and crash while watching YouTube videos or reading comments. BleepingComputer has confirmed the bug on our machines, and it only takes a few seconds to trigger after a video starts. A Microsoft employee has acknowledged the issue and suggested users download Edge Canary, where a fix has been added. However, other Edge users report that this is only a temporary fix and the browser eventually begins to freeze and crash again. For those affected by the YouTube crashes, you can either try Edge Canary until it’s fixed or use a different browser.
Source: https://www.bleepingcomputer.com/news/microsoft/microsoft-edge-crashes-when-watching-full-screen-youtube-videos/