You can buy Hellfire and Diablo on GoG, and they work great. I even used that to put Hellfire on my Anbernic Linux handheld, and that was probably the best way to play it I’ve ever tried.
If they work on the steam deck, I’m going for it. University lan parties in the computer labs with smuggled in beers while playing Warcraft were fantastic.
That is, until they figured out that the one winning strategy was to play Orcs and get blood ogres asap, then just swarm with them. After that, the entire game hinged on the fastest clicks and where you landed for your starting base.