Some workarounds to consider for the time being:
* Install innoextract, then use it to extract the Windows version of the game. Also install 64-bit DOSBox, and you should be able to use it to run the game.
* Find a way to run the old installer on a system running an older version of Mac OS, then copy the files over. Use a 64-bit version of DOSBox to run the game.
* Install Linux on a VM, then run WINE or innoextract to extract the game files from the installer. Then, either run the game in the VM (using a Linux version of DOSBox, or WINE on the included Windows version), then transfer the game over to the host OS and run it with a 64-bit Mac version of DOSBox.
These instructions should also, in the future, be applicable to Apple Silicon Macs (but note that the VM and WINE options require extra CPU emulation, which is slow). You will need to find a suitable DOSBox build for such machines, but seeing as DOSBox works both on Intel Macs and ARM Linux, it should not be hard to port it.