The Anselmian argument in favour of everlasting punishment is fallacious. Here is a brief summary of the argument:
Every sin against God is an infinite sin because God has infinite dignity and the magnitude of sin is determined by the dignity of the one who is wronged. Infinite sin deserves an infinite punishment, therefore those who sin descend into the torturous flames of Hell and remain there for all eternity
This is unbiblical. The biblical view of retribution is “an eye for an eye”: the harm bestowed in retribution should be equal to the harm caused by the offence. Seeing as it is impossible to harm or offend God (he is immutable), sin simply cannot lead to any sort of divine retribution under this schema.
Instead, sin is it’s own punishment as the primary person who is harmed by sin is the sinner. Someone who hates and curses God does not harm God: they harm themselves. And so God never punishes anyone, he only ever rescues us and liberates us from slavery and bondage to selfishness, death, and pride.
There will indeed be a cosmic equalisation, where the rich will be made poor and the poor will be made rich. Hitler will experience the harm he has caused. Rapists will be made to feel the terror and torment they have inflicted. Justice will be done.
But the ending of the story is reconciliation, forgiveness and joy: Hitler will sing songs with the Jews, rapists and their victims will embrace, broken families will reunite.
At the centre of it all will be pure, triune love. The three divine, perichoretic circles that drive the cosmos to perfection. Love wins, Hell loses, and this is the only eternal reality we need to anticipate.