Not sure about the verses you refer to.
Sorry I cannot give credit where it's due, but someone on tol recently described heaven as a restoration of the unity of dimension.
That is, at the fall, time was created, and dimensional realities were created.
So, heaven is in a dimension that we cannot access unless God wills it. (Similar to Paul being "outside of the body in the 3rd heaven", etc)
Somehow, we are in several dimensions at one time according to Jesus Who said we are in heaven, seated on his throne or at his right hand. While we are not aware of this existence outside of our dimension, it is a reality as Jesus says.
Sorry, I am not explaining this well at all.
Anyway, when the New Jerusalem comes down out of heaven from God...
it will be because there will only be One dimension when all else passes away. Eternal Now.