Had also been thinking about asking Codex to boil the oceans in an attempt to fully decompile or reverse engineer that OG of 1990s 4X games, 'Stars!'*, which I have a copy of, so I could have something modern and native for MacOS that kept all the mechanics. Maybe I should just do this instead, will have to investigate.
Alternatively: eBay. Encarta 96 CD-ROMs are available for about $20 in the US, delivered.
EDIT: Here's the other Stars! thread. https://news.ycombinator.com/item?id=49755378
Memories of the ISO mounting program I had; so nice for all the disks to live on the server and just be mounted when needed.