I feel that there will be a new earth after Satan is let loose after The Milinuium and his army is Crushed the second Resurection happans the evil are cast in to hell along with death and al the rest of God's enimes. Then God creates a new earth after the old one is destroyed by fire this could be very well the old earth's core implodeing but who knows. Then a new earth pure and new free of sin will be created with the New Jeruslum (yes I believe a giant cubical New Jersulam will be on the earth.) On the earth where the redeemed will worship God for all eternity in new hevanlly bodies. Where we will see God face to face and there will trully be nither jew nor gentile male nor female only one kind of people the rdeamed.
I think you have been reading too much of J N Darby
I agree. God has been creating a new heaven and earth. The last chapter of Isaiah describes that God is creating a new heaven and earth. It is the theme of Holy Scripture.