This is going to be a bit hard to describe, but I'll give it a go.
I basically tried the "Layer Texture Paint" tactic by having a mix shader with two Principled Shaders with textures (Color, Roughness and Normal) on both ends and an image texture on the FAC. Now, here is the tricky part, on one of the ends of the Mix Shader, there is another Mix Shader with two Principled Shaders with textures and an Image Texture as the FAC.
At the other end of the Mix Shader (first One), there is a Principled Shader, but when I connect that principled shader to an Image Textures, the material breaks and goes all that error pink.
The main problem is on the node on the top(Also, the Diffuse shader was later replaced with the principled shader, both come out with the same problem) This picture shows it WORKING, without the image texture connected. The image texture is next to the diffuse shader.