My understanding is that there is heaven and earth, and heaven mostly has a dual use, though Paul referred to the "3rd heaven".
I see the word used according to the natural and the spiritual, that is, heaven being the sky, and space, and, heaven being the celestial realm. There is the earth and sky, and the terrestrial and celestial.
When we are born from Adam, we are alive in the terrestrial. When we are born from God, we are alive in the celestial. When we are alive in the terrestrial, we experience the input of our senses in the terrestrial. The celestial is veiled by our flesh, and we do not see through that. But when we die in the terrestrial, if we are alive in the celestial, we will no longer be veiled, preferring to be absent from the body and present with the Lord.
In the resurrection, we become again alive in the terrestrial, but I think we won't be veiled anymore, but will be alive in both realms with understanding and perception.
In the new creation, I think the same thing will be true, that the veil will be removed, and the heavenly and the earthly will be a single realm. I wouldn't be dogmatic about that!
In Isaiah, he prophesied of the generations of Jacob continuing forever. Things like this get me thinking!
Much love!