Comment by pseudosavant

This isn't even a strictly Linux problem. On Windows, Edge has by far the best encrypted streaming playback using their PlayReady DRM. Many services like Netflix will only do 4K for Edge. Chrome is often 1080p, and Firefox was 720p last time I tried it.

Same situation on Mac where Apple's Fairplay DRM enables 4K playback in Safari, but Chrome and Firefox have the same limitations as on Windows.

Last time I tried to use Firefox on Windows as my daily driver, video playback was one of the biggest gaps that made me go back to Edge.