I cant believe no one has gone for the best ones. ancient is always better, erebus, tartarus, muspellheim, Hel (it came from norse mythology, christians used it to convert them.), duat, nu, and probably quite a few more that I'm missing
I'd say mostly erebus, tartarus or muspellheim (I mean come on, the land of fire?)
I don't see a problem with hell. Hell comes from the Ancient Norse god of the underworld. If not hell, I think use Ancient Greek mythology and call it underworld, Hades, Tatarus or (my favorite) Erebus.