What's the non-mediocre alternative to Windows, that allows you to choose your hardware (i.e. not macOS) and that is usable by everybody (i.e. not Linux)?
I don’t believe it’s possible to create a non-mediocre product of such complexity, especially if you need to support a variety of hardware. Without this requirement, iOS comes closest, though the UI discoverability is often abysmal.
And Linux is mostly good (and best, depending on hardware) now if you don’t need specific unsupported software.
iOS doesn't even get off the starting blocks for serious software. Can you score movies on an iPad? Can you develop console games? Can you use Blender? Houdini? DaVinci Resolve? Other industry standards?
Even Linux lets you use Blender, Houdini and DaVinci Resolve natively.
And Linux is mostly good (and best, depending on hardware) now if you don’t need specific unsupported software.