I'm on a Windows box. I'm in a similar boat as you and basically caved when it came to gaming and built a Windows box. I don't love Windows but I mostly just use Steam anyways.

At one point I used the version sold by gog.com

That version worked on OSX for a while but it doesn't look like that's the case anymore: https://www.gog.com/game/total_anihilation_commander_pack

BTW: I've run TA on a VM before. I think I used VMware Fusion. You'll still need a Windows license but at least you won't need extra hardware.