@FedeKrum you posted that question a fair while ago. I have exactly the same problem. Have you found any solution?
I remember that the keymapper worked flawlessly in earlier versions of Recalbox.

@voljega
Thanks for your proposal. Concerning DOS, I am in general a freak of isometric games.Because of limited time, I concentrate on this category. For the moment I own all of the games in the time they came out, and frankly, most are cheap also from GOG.
I want to give a try to another pearl "Lara Croft and the Guardian of Light". If possible.