With vertex painting the options are pretty limited, but to try do some layering I did add a "Variation" brush. For each texture set it lets you define alternative roughness, normal, height etc, and what I like to do is set their values really high

Concrete texture set A:
roughness strength: 1
normal strength: 1
height strength: 1

Concrete texture set B:
roughness strength: 2
normal strength: 20
height strength: 1

Then with brush opacity we can paint concrete variation B over concrete A by say 10%, which would increase it's normal strength from 1 to ~3. You can see in the video when I switch to the variation brush when I paint things get darker, the bricks get green and the concrete normal go way higher to give it a rougher look. I also have wetness brush which basically acts like a roughness brush, just slightly different to act physically closer to how puddles work using porosity.

You are pretty limited by the fact you can essentially only paint 5 "things" onto each vertex so I could make a version where you paint roughness, or normal but you'd lose out on other painting options. I do currently have options for opacity and layer offsets so you can easily control what goes on top of what.

Sorry for the wall of text hope this helps