indeed it is a bit mono-cultured as almost every linux distro uses systemd per default… i remember the time when arch changed to systemd rumors rumors… but here we are using archlinux as the base with systemd in its core…
If systemd-boot then as an option in addition to the way to use grub and also rEFInd.
My understanding of it (limited) suggests that it just uses the same mechanism as rEFInd does for booting vmlinuz-linux - so you would lose the 'intervention" from grub for special circumstances. I wonder if systemd can boot grubx64.efi?
Different machine? I wouldn’t mess with the current setup either! Also I don’t know if systemd boot would work in qemu - don’t see why not - you cold try that. (Apparently rEFInd can work in a VM).