Or slave two copies to yours and get "side view" which was only supported for a few releases IIRC - https://doomwiki.org/wiki/Three_screen_mode

Yes, Doom with multi-monitors! There's (at least) one video on Youtube showing it in action with 3 monitors plus a fourth one with the map: https://www.youtube.com/watch?v=q3NQQ7bPf6U#t=1798.333333