Unfortunately that's a business decision, not a testament to the greatness of Edge. The different browsers and properties of the PC constitute a "security level" in the DRM module, and Netflix ties its offerings to the different security levels. You could say that with IE, you have the least control over your Netflix stream and that's why they let you play their content in 4k.
Nevertheless, Edge could be a good browser otherwise. What I wanted to point out is only the point about 4k Netflix.
Still better than standard Chrome, which if I understand correctly cannot implement any vertical tabs because of the lack of side pane. But yes, the killer feature of TST is the tree function.
Only browser that does 4k Netflix.
Fast and least resource/battery use on Windows.
Ublock origin still works.
Yes, Firefox is my first choice. But Edge is actually good.