Also the mentions in the bible are either by Jesus, Who was famous for speaking in parables and metaphors;

This idea of speaking in parables and metaphors has been used as a means of control by the Catholic church. It's one of the reasons Vatican 2 was such a mindfuck for the Church as it stopped the requirement for Latin Mass and Latin Bibles. It's used in instances like this where the preacher can delete or twist various passages to fit with the layman's culture and ethics. That's very duplicitious on their part and that's why this hand waving exists.

Also highly metaphorical. And turns out the image of eternally burning is a pretty good metaphor for having a bad time forever.

1. Metaphors, parables and and even paradoxes by various prophets (something Jesus didnt talk about) are extremely common in other religions. That's taken into account, it's not rocket surgery. If Chaung Tzu wants to compare a content man to a knotted pine that's spared from lumberjacks, that's a parable compared to Jesus and loaves of fish. That's fair, interpretations of parables results in things like Arianism.

Saying a 7 headed dragon is a metaphor is like saying Valkyries scooping up warriors and taking them to Valhalla or the plains of Freya is a metaphor for Odinists, or that Yeshu of Nazarene isnt actually boiling in a cooking pot full of shit for all eternity in the Talmud. You can say it's not real, it's not literal, but that is a uniquely Jewish based religious concept (aggadah) and does not exist out of that very narrow scope. Religions believe gods live on Olympus, Valkyries come to rescue the fallen, that a power named the Tao encompasses all, that we are stuck in a literal karmic rebirth cycle and seek escape, that a mountain in the middle of Mongolia is alive and blesses its tribesmen with thunder and rain and so on. The reality is Christianity abandoned gospels that would have fleshed out but pronounced a less than ideal picture of Jesus, such as the Gospel of Thomas the Brother, which has Jesus attacking people with clay birds as a kid because he was the town warlock, noted in Muslim and Jewish texts yet absent in Christian ones, and uses clunky aggadah arguments to create this ethereal place where anything a profound schizophrenic says (that was chosen because the authors really liked him preaching about the Fall of Rome) is hand waved away as metaphor. Real religions don't do that. Even the Jefferson Bible had to try to get rid of most of that shit just for the parables to make sense with logical consistency. This is the most frustrating thing when talking to Christians, your utter lack of faith in your own texts (and rightfully so because it was assembled by guys with axes to grind) and hand waving of fundamental logical inconsistencies is appalling.