None of these solutions are any good unfortunately. Mostly because they rely on cheap cop-outs or because they are narratively unsatisfying.
1) and 5) are basically the bad ending, that people won't like, myself included. And that's important, because people want to have a good payoff, one that made the journey worth it.
4) is technically fine, but unsatisfying because it doesn't solve the future issues I outlined, and it would make no sense for the atrocities of either Ella or H.E.R.O. to be forgiven. Also, the world might be screwed afterwards anyway.
2) and 3) are very cheap escape routes. 2) would negate all the work that went into characters and plot, it's basically a nuke button for 90% of the work that came before. 3) is just lazy and much the same way, plus it doesn't solve the problems long-term.
The real skill of a writer is to not get themselves stuck in a corner in the first place, or be very skilled at maneuvering your way out of them without destroying previously established rules, or breaking audience immersion and investment. So far so good, but with stakes this high, it becomes hard to manage.