Buy the GoG version. When it's not on sale it's only six bucks, and if you keep watch you can probably get it for two in a reasonably short wait...and GoG has it set up to just run.
You can also download PRAX to play the game in 1920 x 1080 and with some other visual improvements. https://alphacentauri2.info/index.php?topic=14308.0