Well, the time it would take is merely a microscopic fraction of the time you yourself, as a Jew or Noahide, will live on this earth - in the Era of Redemption.
What does it take to get a ticket of entry into that world of paradise? The conditions are specific.
A Jew automatically gains entry, no matter who he is (barring a few exceptions perhaps).
For a Jew, if he receives punishment for misdeeds, gets punished in this world. The few sins he commits in this world "cost him" in this world. That's to ensure his free ticket to the eternal world-to-come.
A righteous Gentile, or one who follows the "7 Noahide Laws", also receives remuneration as does the righteous Jew. The same accounting procedure is used. He too has a present account settled here, so as to receive a future credit.
The Gentile who misbehaves is reckoned with differently. For every deed of goodness or kindness he did he is "paid for" - in this world. Paradoxically, a villain's success may give the impression he's a person of "goodness".
But G-d, Who is fair, knows better. The non-righteous Gentile is not cheated out of his merits. God "pays" this person in this world because - for this person there is no other world to go to. This world for him is a dead-end.
This is the meaning of the verse in Deuteronomy 7, 10, "And he pays his hated one the face value [in this world] in order that they forfeit [the world-to-come]."
This is also the meaning of another verse in Deuteronomy (32, 4), "He is a faithful G-d [Who will grant the righteous their due portion in the future] and He does not cheat [those criminially-behaving Gentiles from their due recompense in this world]."
The world-to-be is reserved only for the dispensation of good to the righteous - who earned their destiny in the brief trial period they spent in this world.