Hell isn't even a biblical concept. Its literally made up. Where people think the Bible talks about hell, it says "lake of fire." That's an Egyptian concept that has been wildly taken out of context. Rebirth is entering the lake of fire. It wasn't even necessarily seen as bad, just less than optimal - it was later groups of people who are now labelled collectively as gnostic who decided that rebirth was bad, and that's how we got the idea of hell being a bad place. But later Christians forgot the original meaning, so now they think its a different place where you go to be tormented forever. That's already happening. Its here, now. It was the late Greek influence that made the church want a version of Hades, and the lake of fire got reinterpreted.
Similarly, heaven was never a separate place that you go to. Jesus said unambiguously where heaven is - right here, right now. These are not opposite concepts. They are the same.
