Many disputes are semantical ones. This is one.
What is 'literal fire'? If 'literal fire' is the exothermic rapid chemical chain-oxidation of a fuel supply...then for there to be literal fire in Hell, there would need to be material fuel and an oxygen atmosphere.
^THIS.
I'm not aware that anyone ever intimated that Hell had a wood supply, or air to breathe.
So, it would seem that the fire is more akin to the fire that did not consume the burning bush. It that were 'literal fire', then by definition the bush would have been consumed. So, better to describe it as 'miraculous fire' which is not subject to the same rules.
So be careful tossing around the word 'literal'.
Finally some sense. Whatever this "fire" is, we know that those who are currently in hell are being tormented by it. Yet we know that there are no physical bodies in hell ... not until the resurrection. Consequently, it's probably not the same combustion fire that we know here on earth. Rather, it's something that can directly afflict and torment the sensible part of the soul, rather than through the intermediary of the body, thereby making it more painful than any fire could be on earth as it burns through the body. It is clearly, based on Scripture, not just a metaphorical fire caused by spiritual pain, but rather something that causes pain of sense, but in order to directly afflict the sensible part of the soul, it has to be something more or something different in quality from the fire that we have here on earth. Just as Our Lord's glorified body had different qualities than an ordinary non-risen body, hellfire most likely has some incorporeal aspect to it as well.
So, I agree that using the term "literal" is problematic.
No, it's not metaphorical in the sense that purely spiritual pain is referred to as "fire"; it's a true
poena sensus (pain of sense) but it must be of some nature as to be able to directly afflict the sensible part of the soul (which is on its own immaterial when separated from the body).