Did you consider WINE? Some other official Mac ports of PC games work in custom WINE configurations.
FD really don't need wine, they have good coders who did initial OpenGL renderer for MacOS. Issue was that Apple stopped to support OpenGL at version 4.1, but Horizons need 4.3. Yes, it is that bad. If only Apple decided they want to keep supporting OpenGL for at least several years FD wouldn't have to do this (albeit considering Apple moving to ARM it really would just keep ED on MacOS for a while but not forever).