The words “new heavens & a new earth” are found in 2 Peter 3:10-13 &
Revelation 21:1. Does that mean a literal new physical universe and earth
or is it a way we as humans can relate to heaven?

Well, put it this way. If we can assume that the “new earth”
is a physical place at all, then it would have to literally be a new
earth, at least in some sense. I say this because in the context of the 2
Peter passage you refer to, Peter declares that, “The heavens will
disappear with a roar; the elements will be destroyed by fire, and the
earth and everything in it will be laid bare.” It seems undeniable that
the picture of the new heaven and earth in Revelation chapter twenty-one
is highly symbolic in nature. The New Testament makes it very clear that
the wonders of heaven are beyond human description or comprehension.
Therefore, I will not speculate on whether the “new earth” is a physical
place or not, but I can simply say that if it is, it will indeed be
completely new.

John Oakes