Use linux-image-cloud; use a modern hypervisor with no legacy devices (only virtio etc); use tiny-initramfs; mask systemd-networkd-wait-online.service; add cryptomgr.notests noreplace-smp to kernel command line.
I think that's all, and use a moderately fast CPU (i7-8700K which is already 5 years old).
I'm talking about the time taken by OMVF/SeaBIOS or whatever equivalent in the VM; which is why I asked about the type of VM/Hypervisor because that might not apply.
Use linux-image-cloud; use a modern hypervisor with no legacy devices (only virtio etc); use tiny-initramfs; mask systemd-networkd-wait-online.service; add cryptomgr.notests noreplace-smp to kernel command line.
I think that's all, and use a moderately fast CPU (i7-8700K which is already 5 years old).