Earlier quoted context omitted.
I have an old photo of my girlfriend with her cousin when they were young, wearing Christmas dresses in front of the tree, not long before they were separated to other sides of the world for decades now. The photo is itself low quality on top of the photo itself being physically beat up. So far no model is willing to clean it up :/
There are reddit communities (I admittedly don't remember which, but could probably be found from a simple search) where people will offer their photo editing skills to touch up the photo, often for free. Could be worth trying a real human if the robots are going full HAL 9000 and telling you they can't do it.
People sometimes do it for free ("my son died, and this is the only photo I have") or for an agreed upon tip.