This video talks about running macOS inside Linux VM.
I was not able to install the recommended Manjaro Linux on Hyper-V in Windows 10 Pro. While booting from the ISO image there was an error about the graphics card.
Instead Gentoo I used Ubuntu 20.04.1
I also had to use PowerShell to expose the virtualization extensions on the Ubuntu VM:
Set-VMProcessor -VMName "Ubuntu 20.04.1" -ExposeVirtualizationExtensions $true
To enable nested virtualization in Oracle VirtualBox:
cd C:\Program Files\Oracle\VirtualBox VBoxManage modifyvm ubuntu2004 --nested-hw-virt on bcdedit /set hypervisorlaunchtype off - this disables the auto launch of the hypervisor. To enable it again: bcdedit /set hypervisorlaunchtype auto