I was hoping I could run my windows install both as dual-boot and inside VM on my main OS... and I can! Turns out it's just one line for virtualbox, only thing is that user has to be able to access
/dev/* stuff (so needs be in
VBoxManage createmedium disk --filename='path/to/disk/file.vmdk' --variant=RawDisk --format=VMDK --property RawDrive=/dev/nvme0n1
And it just works. Useful stuff especially when migrating accounts or just for accessing some windows only stuff quickly without rebooting.