I run a setup where I have 10.13, 10.14, 10.15 and 12.0 installed on dynamic APFS volumes and big Sur (11.0) as my main. While not exactly VM I can switch betwe

I run a setup where I have 10.13, 10.14, 10.15 and 12.0 installed on dynamic APFS volumes and big Sur (11.0) as my main. While not exactly VM I can switch between them as a matter of rebooting, filesystem is shared and setting each one take 15 minutes as you can download original install images.