Edge (Spartan or Legacy) had a big fight with YouTube that YouTube was doing a hidden (not visible to users) DOM animation underneath the video player in a way that Chrome ignored but tanked Edge performance. There were several release cycles where Edge would specifically target that hidden animation performance, only for YouTube to make the animation worse and ratchet it back.

I lived through that as a user. (I was one of the like 5 Edge Spartan users, I know, lol.) I could see the dumb animation in dev tools and manually delete it for better performance. It was a nice thing I had some technical skills. I know for mainstream users the solution was "watch YouTube in Chrome".

It's hard to find to other sources because Microsoft intentionally broke the SEO on the Edge brand and you know Google is the only other major search engine. Not that they'd intentionally down-pagerank bad news about a Google property, I'm sure.