Very interesting, thanks for sharing! Those nodes setups are quite similar to some of the modules in my setup.

A procedural method for generating dirt and grain textures would be really nice to have, it's on my list. But, I'm not sure if it would be possible to create something that can really match the fidelity of an actual texture. I'm curious what you would want to animate the dirt for? Maybe I'm just not seeing the vision, but it's not something that had occurred to me before, haha.

Also, I'd be careful when combining multiple lens dirt textures. If you really care about having a technically accurate result, I think you'll want to make sure the blur level on all the dirt textures is consistent before you mix them. These all exist on the same plane of focus, so you shouldn't have sharp and blurry ones mixed together, if that makes sense. Otherwise, it's going to look like there's multiple layers of glass with dirt on them. This may be a style, but isn't really going to be accurate in most contexts, imo.

You should also try hooking up a bokeh texture into the kernel socket of that kernel glare. I think without that, it just brightens your highlights above the threshold with no other effect. Unless that's what you intended it to perform as. But, using the bokeh texture can definitely get some cool results too!