What operating system it runs doesn't matter.
It does matter. What happens if the OS includes a virtual Amiga chipset functions?
Running Linux on an Amiga still leaves you with an Amiga.
Such a set-up still requires Amiga's Kickstart functions to boot into 68K Linux.
Running Windows/MacOS on other hardware doesn't turn your machine into a X86/Mac.
Running MS Windows NT 4.0 on DEC Alpha AXP or PowerPC or MIPS will turn your box into a MS Windows NT 4.0 box.
Once upon time, Microsoft has a vision of running Windows NT everywhere. Except they forgotten the transparent recompiling concepts (e.g. dotNET framework).
Note that SoftWindows 95 (for MacOS platform) was based from the licensed MS Windows 95 source code. In a sense, it’s closest for Microsoft to release a MS Windows 95 for the PowerPC platform.