Yes… I have seen this before and played with it. This was a good attempt at emulating the behavior of an app like Substance Painter. However… the core problem is that in order to paint textures you need very complex and deep functionality. When using Substance, I have to variously consider: the texture channels (e.g. color, roughness etc), the many layers that may serve these channels, the baked texture channels (e.g. ambient occlusion, normals etc), the many blend modes, masks and adjustments that serve and interconnect all these.

I doubt that anything other than native blender functionality could serve all this with any elegance.

I teach substance painter and it does a good job and hiding all this complexity until you need it. It is very common for students to underestimate it as an app… to view it as just photoshop for 3D.