I posted too quickly on Monday... other options include booting into Snow Leopard, if you still have a bootable SL disk around, or getting a junker PC.
I've kept a bootable SL partition just in case I needed to run an old PPC app, as SL still has the Rosetta emulation mode to run PPC apps on Intel Macs. I've not needed to use it to date.
Running Windows under Parallels in order to run old Windows versions of AC requires buying Parallela and a Windows license. You can probably find an old junker XP machine somewhere cheaper.
One of the forum moderators
AC 27 USA and earlier • macOS Ventura 13.6.9, MacBook Pro M2 Max 12CPU/30GPU cores, 32GB