I've been using Parallels Desktop for many years now. It's allowed me to support customers on lower-end machines with a variety of operating systems (even as far back as Windows XP!). I recently upgraded to an M3 MacBook Pro. While most everything is working fine, Parallels is a huge disappointment. Basically, it's only commercial application is virtualising Win11 ARM: - No Intel versions of Windows can be used - No older versions of macOS can be used - Current version of macOS function, but have no access to devices, e.g. attached via USB (i.e. useless) Unless there's a clear path to changing this, I'm going to explore other options to replace Parallels - its functionality has greatly diminished but the cost continues to climb and no one seems able to answer support questions about the current version. I'd be interested to know if anything more is planned for the future of Parallels - seems like it's just coasting.
Prior to virtualization support for older OS systems was provided by keeping a set of machines up-to-date and available to troubleshoot issues. The use of a Parallels VM improved things in this regard, however, the move to ARM architectures has changed everything. You must now consider keeping an Intel-based machine around and up-to-date to service the customers with these older machines. My prediction is that in 5 years the most powerful Windows-based machines will also be on ARM architectures (you already see signs of that today), but since hardware replacement sometimes takes 5+ years, the older Intel-based CISC architecture machines will still be around. Good luck!
Parallels is able to run older versions of macOS going back to macOS 12. Apple did not have virtualization support for older versions for apple silicon Macs.