The Classical concept of God is one of completion and perfection - an individual such as you or me cannot add anything to complete perfection.
Therefore any human creation is constrained within already-existing divine perfection; and human creation is never substantive, never necessary - our best efforts can never (even in theory) make a real difference to already-existing perfect completion.
However, my understanding is different from this; I understand God's creation to be growing, developing through time; and with endless scope for individuals (such as us) to contribute.
The difference between this mortal life on earth, and Heavenly life, is that our creating happens in the face of the dominance of change, of 'entropy' - a tendency for what-is-created (including our-selves) to relapse towatds primal chaos.
Whereas Heaven is a creat-ing world, open-ended, continually 'under construction' - a world in which there is both new creation and permanence: a world of 'negentropy'.
How? Due to Love. Heaven in a world in which creation is harmnised by Love; possible by the eternal committment to Love that is made in resurrection.
So - there was a primal chaos; then God made from it, and in it, a Heaven of his own creation. Since Jesus, there is the Heaven in which God's creation is joined with those of his resurrected children.
We live in the world between these worlds; but although ourselves in this transient form, may create in ways that are carried through to the permanence of Heaven