... a standalone installer for QEMU for Mac OS?
The xPack QEMU Arm is distributed as standalone archives, for all platforms, including macOS:
They do not even require install, simply unpacking the archives in any location is enough; this can be further automated with xpm, which is also very convenient for CI.
Time permitting, I plan a similar binary distribution for the latest QEMU too.
Regards,
Liviu