[OT] Multiple macOS recommendation sought

[Paul Dupuis]

A problem I have struggled with for decades is software testing on the 
various versions of operating systems our software deploys on.

For testing on Windows, we use Virtualbox with Virtual Machines (VMs) 
for Windows 7, Windows 8.1, and Windows 10 (we have yet to try to build 
a Windows 11 VM)

For macOS we have tried a multi-boot system, a mac Mini with hard disks 
partitions to boot to OSX 10.9, 10.10, 10.11, 10.12, 10.13, and 10.14 
(Mojave). We tried a partition for 10.15 Catalina, but were were already 
experience problems switching between boot partitions where the Mini 
would forget what Startup disk it should boot from. When we added 
Catalina, the problem became worse, trying to go from Catalina to an 
older OS on reboot or vice versa would fail.

So we tried a Mojave (10.14) laptop with Virtualbox and build a Catalina 
VM. This worked well for Catalina testing. We like VMs for the ability 
to reset to a snapshot or to clone them. We added a Big Sur VM, but 
playing video does not work in the VM and Virtualbox's latest release 
has not fixed this and macOS VMs are not really supported, even on mac 
hardware. We just tried a Monterey VM and it is unstable. It will crash 
and reboot after a random amount of time.

Some sort of virtual machine is very appealing because of the ability to 
restore the machine to a snapshot after testing or to clone it. If 
testing messes something up, you can always get back to a known state 
without rebuilding a computer.

What have other people's experiences been? Does anyone have a more 
stable, easier solution?