Magic Dosbox on Steam Deck? Neat idea, I would love to see that. 😉
But the way I understand it, it’s next to impossible to have the same kind of overlay control scheme in Windows, let alone in SD’s Linux environment.
I haven’t used Dosbox at all on my my Deck so far, but I guess you could create some very cool layouts with the built-in controller config tool. And maybe it’s possible to add single DOS games as non-Steam game to the library via Steam ROM Manager, so your can bind individual controller layouts to them?