Orkhepaj: yep win10 and win11beta :P
timppu: I once dualbooted Windows 7 and Windows 8 because I wanted to check out how 8 works while still keeping 7 for now (which was good because in the end I hated Windows 8 with a passion).
The Windows 8 installation corrupted the Windows 7 partition unbootable. :( That was some bug or oversight by Microsoft, apparently they had not anticipated someone would try to run both side by side. Windows 8 apparently treated the Windows 7 partition as some extra data partition, and changed something in it to make it unbootable.
So, yeah, no...
Agreed, similar issue with macOS 13 with any earlier version. They started using a new filesystem with SSDs, then one version later, number 13 made it work with HDDs, too. Upgrading or installing it converts the whole internal storage disk. As such, installing macOS 12 on an HDD (like the Fusion Drive they sell by default) fails to recognize the new filesystem and reports it empty, so no partitioning the disk without wiping out 13.
I am going with external for all operating systems now, and just plug in a disk and boot the computer. I have only done that lately, with piCore (RPi obviously) and macOS, and those work great that way.
Have yet to try external booting with MS Windows (no copy available, unlikely to get around to trying it at this point), only the free virtual machines with IE and Edge for testing.
I now avoid the internal storage and whatever operating system is installed there, at best just leaving it alone as a worst case scenario recovery system if all the external disks fail to boot (yet to happen).