To me, if we wish to view things in terms of a cosmic fall, we need to consider the intended cosmic role of man.
As you know, the whole point of my forthcoming book is to deny that the natural creation is fallen in the sense that’s usually taken, so we don’t need to be looking for the flaws in distant galaxies (let alone the beginning of entropy).
But if we take the achieved role of Christ as being the intended role of Adam (and my discussion on this usually begins in Psalm 8 as interpreted by Hebrews 2), then God’s purpose was to fill creation with his glory through mankind.
Such a plan can be fruitfully discussed in terms of God raising the humble and humbling the mighty, as a “naked ape” on a lowly planet gets to judge the glorious angels. If it seems implausible, it’s only as implausible as the eschatological hope we have in Christ of a new heavens and a new earth (well described by N T Wright as Jacob rightly says - welcome Jacob). Then the bets are off about entropy and everything else.
But meanwhile, the whole cosmos would be involved in that frustration of being promised the intimate, permanent presence of God and yet being denied it because of human sin and remaining perishable. Paul’s use of that “frustration” imagery in Romans is highly metaphorical and spiritual, I guess, because it’s ahard to imagine how a black hole, or a lump of roick come to that, could be groaning in frustration.
But biblical thought, like ancient thought generally, has much to do with right order: just as Abel’s blood “cried out from the ground” because of an unresolved murder, I think creation is pictured as disrupted simply because sin exists in it, God’s purposes are (apparently) thwarted, and “all is not well with the world”.
Additionally, since God does judge sin in history, and nature is often his instrument, at least the earthly creation is turned to uses it would (again in personified language) rather avoid - it was to bless man, not curse him.
Additionally still, of course, there is the damage inflicted on man upon nature, but like the last point, none of that seems to touch the vast cosmos out there. If we deny some huge change after Eden (and the Bible gives not one hint of it), then it seems to me the best lens is the new purpose of God for it, interrupted by the Fall of the absurd creature God had chosen to bring it about - and who, in Christ, actually does so as the cosmic drama unfolds.