is the KVM images compatible with Qemu emulator? if so this is great alternative for whonix over vbox as another (better) free software cross platform hypervisor.
Vbox having terrible issues with Debian due to its lack of development/upgrades in Debian leading to severe bugs like recently one upgrade deleted/corrupted vbox which needed to be installed again from debian sid. (even installing vbox from vbox repository on debian buster it will not make it through, only sid version currently working which not is wise to mix contents with stable repo…).
Qemu supports GNU,Mac,Windows: