I use systemd-boot so it was pretty easy, and it should be similar in GRUB:

title My boot entry that starts the VM
linux /vmlinuz-linux-zen
initrd /amd-ucode.img
initrd /initramfs-linux-zen.img
options quiet splash root=ZSystem/linux/archlinux rw pcie_aspm=off iommu=on systemd.unit=qemu-vms.target

What you want is that part: systemd.unit=qemu-vms.target which tells systemd which target to boot to. I launch my VMs with scripts so I have the qemu-vms.target and it depends on the VMs I want to autostart. A target is a set of services to run for a desired system state, the default usually being graphical or multi-user, but really it can be anything, and use whatever set of services you want: start network, don't start network, mount drives, don't mount drives, entirely up to you.

https://man.archlinux.org/man/systemd.target.5.en

You can also see if there's a predefined rescue target that fits your need and just goes to a local console: https://man.archlinux.org/man/systemd.special.7.en