I created a simple self-contained script that does the following basic steps:

• Download an EFI BIOS
• Download an Arch Linux ARM bootable ISO image
• Create a raw data image with a FAT filesystem that contains some scripts to use on first boot, and an empty raw Linux image
• Boot up ISO image
• User runs a command to mount and execute a setup script
• Setup script partitions the empty raw Linux image, downloads and extracts a base Arch Linux ARM image into it, and shuts down
• Host script converts the raw Linux image into a compressed sparse qcow2 image
• Creates an ArchLinux.app bundle that can be double clicked in the Finder or added to the Dock to run the VM

There were a few bits that were a little tricky to figure out:

• Due to differences between x86 and arm boot processes, a bootable ISO doesn't seem to be useful for making a bootable arm system, but it is useful to create a Linux filesystem
• A data image needs to be used that has a FAT filesystem, as the Mac host and the Linux ISO can both access FAT
• If you create an empty Linux image in the FAT filesystem using the Linux dd command, the Mac may or may not be able to copy the image out of the FAT filesystem. Seems the Mac is fond of saying the path name is too long. This is solved by having the Mac dd command create the empty Linux image.
• I downloaded an SVG image for the App bundle icon of the big blue Arch "A". I found the gm cli tool could not convert this particular svg into png correctly, it was a crappy image, missing some of the colours. I used GIMP to do it manually instead.
• I wanted one self-contained script, so all the scripts that need to be created on the host and in the Linux VM are contained in Heredocs inside the script. The script runs in about 5 minutes, with a few user interactions. I find the performance is pretty good, it boots really fast.

I did find that using a graphical X system seems to have stability issues that cause apps to crash, so I'm only using it for the console. I really just need docker and podman, as they hard to get working on the Mac, but easy as can be in Arch.

Overall, I'm quite happy with the result. Try it out at https://github.com/bantling/tools/tree/master/qemu-vms, which explains in detail how to use it.