iirc, from a photon's "perspective" the entire universe is at once.
which, knowing that objects are leaving the visible universe due to expansion even as the bounds of the visible universe expand, leaves me with a question as to what happens to those photons?
Even though probably no one will care, I'll answer this anyway.
Objects beyond the edge of our observable universe are only travelling away from
us faster than the speed of light
relative to us. They aren't actually travelling faster than c relative to observers that are closer to them. Also we appear to be moving away from them faster than c and therefore are not visible to them vis a vis the electromagnetic spectrum. As for some other observable technique they may have, I've no idea.