Install High Sierra on MBP-M3 via Parallels: Possible??

Apparently it is possible to run High Sierra on a silicon Mac using UTM. However, the performance won't be good as noted in the article.

See: How to run macOS 10.13 High Sierra on Mac M1 arm silicon

No.

Virtual machines get their speed by running the same type of machine code as the host CPU. (They let the CPU directly execute as much of the guest code as possible.). High Sierra is built for CPUs that run Intel/AMD machine code, not those that run ARM machine code. So it won't run in a pure virtual machine on an Apple Silicon Mac.

There is a project called QEMU that can do emulation. I have not been following QEMU closely, but my impression is that it is not anywhere close to being a solution for running Intel versions of macOS on Apple Silicon Macs. Not just because of the slow performance of emulators; more as in, "could you even get it to work at all?"

Servant of Cats wrote:

There is a project called QEMU that can do emulation. I have not been following QEMU closely, but my impression is that it is not anywhere close to being a solution for running Intel versions of macOS on Apple Silicon Macs. Not just because of the slow performance of emulators; more as in, "could you even get it to work at all?"

FYI, there is a third party app which provides a GUI interface for QEMU on Apple Silicon Macs called UTM.

https://mac.getutm.app/

However, like you mentioned, I'm not sure it would be possible to even install an older Intel version of macOS using UTM/QEMU. Since QEMU is a machine emulator, the macOS installer will not see the QEMU system as a valid Mac hardware.

https://www.parallels.com/products/desktop/resources/

"Supported Guest Operating Systems (Mac with Apple silicon):

Only Arm versions of operating systems are supported."