Doom's own private Hell
...would probably look something like this. Four scans from Fantastic Four #570, the first issue of the new Hickman/Eaglesham creative team.
Reed and co. defeat the Wizard (yet again). The Wizard believes that, based on the same math Reed has seen ("math is the language of God"), the world is doomed. Reed's out to fix everything somehow, still. While in his lab, he meets up with three mystery men, who turn out to be alternate versions of himself. They head off through a gateway to another reality...