We're already in hell.
Between the illusory and reactive(in contrast to suffering which is proactive/makes itself known and always comes first) state of pleasure, the measurement of time and how it's appearance by nature can only ever be that of something to be lost or taken away, as well as the fact that if we go long enough without some sort of stimulation or distraction the lack of stimuli itself becomes a very severe form of suffering all it's own, I don't see how this couldn't be hell.
The only lingering fear I have remaining, at least regarding death, is the idea that somehow I might not remain dead, and I'd simply be reincarnated as someone else, or that I'd be forced to live my life again. Of course even if either of these were actually the case, there would be no continuity between me and the supposed "me" who would experience another life, it's no different than worrying about the pain which could befall another person. So it's not an idea that bothers me too much, just something I think about occasionally.
But I don't see how inceldom would be any worse for atheists, as like me, they also assert that when you're dead, it's over. You don't have to worry, strive, try, or dream when you're nonexistent. As far as I can tell, nonexistence is better than existence by every measure, as people with their lights permanently out don't have preferences. If you have no desires, no pain from which to escape, no needs constantly nagging to be satiated, and no preferences which you're attempting to satisfy, then by my standards that certainly constitutes true contentment.
The absence of a state of existence isn't something to fear, if anything it should be embraced.