but like, all I did here was add 1 CURVES layer (with the default set to "DARKER" instead of manually editing the curves graph, where it would be CUSTOM) that is masked over the render with a ~300pix soft brush, and then an exposure layer with all 3 sliders slightly turned up a bit:
i.e.
it results in:
which is a very basic change, but I think it just brings the focus of the sig towards the render (focal point) by making the outside edges of the sig darker via the masked CURVES adjust, and the exposure just adds a universal lighting/exposure to the entire piece to make it more uniform looking.
the difference is very minor (maybe opening them in seperate tabs and switching back and forth makes it easier to see what I mean). Some people may prefer your original without the adjustments, but i think it kind of just looks a LITTLE bit flat / lacking depth.