DOS is the perfect place for “Dune”. The 30yo game, that is.
It's not really an RTS a la the more famous Dune 2, but a sort of adventure/strategy mix. The appeal, though, is just in how luscious it is. It's a bit dizzying, beautiful (remarkably so, for the era), and full of soul in a way that few games of the era were. The Adlib Gold soundtrack in particular remains an amazing work of art too: https://www.youtube.com/watch?v=gUfGyfbzl9k
To get you into the Dune mood :)
It even has clips from David Lynch's movie.
Sigh, I remember getting the CD-ROM version with my first multimedia PC and playing this game...