Greetings, @d-pend. Absolutely mesmerizing post.
Coincidentally, i just wanted a couple of days ago a biopic about Bart Millard and the process that led to his composing "I can only imagine".
It was a beautiful movie. It's hard, even for non-believers, not to be moved by human transformation for the better.
I was intrigued, though by the fact that the song became such a hit, and yet it said so little, and then i remember a visit to a museum in Ciudad Bolivar, Venezuela, where there was this canvas which for me contained nothing but a blank , irregular, granulated surface. The title of the work was "Imagination".
Our conception of heaven or the afterlife, not having a reliable (for lack of a better word) source or informant who has been there and come back to tell the tale, is subject to personal projections, i guess.
This poem has taken me there. To the possibility of a wild "zoomorphically pure" scenario staged on our own "spinning world-ship."
It is certainly surreal, the the best Dalian sense of the word.
This heaven of yours, where

the rush of the wings—
Burning, limitless, wild.
Above in the firmament [is] lit by soul
Where hopes and dreams lay mild.

offers an inquisitive glance at the contrast between our spiritual pursuits and the worldly concerns (hopes and dreams) that somehow seem to hinder the spreading of our wings.