1. Create either a URP or HDRP project
2. Install Polybrush package
3. Import the sample shaders from the package manager for the corresponding SRP
4. Create a plane and assign the material to it using the provided Lit Texture Blend shader from the sample
5. Open the polybrush window and browse to the "Paint Texutre" section
6. Make sure to select the plane

Result
From the texture panel, we don't see the AlbedoTexture1 slot