There's the free AROS for that, and the less talked about but arguably cooler nonfree MorphOS. If you have an old PPC mac try a trial of MorphOS on it, it's a very interesting little system

It's about a million miles away from that. It's a 68000 CPU emulator, with no Amiga hardware, and just enough OS structures sprinkled into memory, such that quite a few Amiga CLI utilities work.

What you're looking for is a ROM with a full implementation of AmigaOS, that can manage real Amiga hardware: that is only possible with the official ROMs or projects like AROS

You can use the ArOS roms for m68k and Aros m68k itself, but you need to set a highend setup.

There is an open source version, named AROS, which you can use.