Misunderstanding UV Workflow - Blender to Painter

I'm new to Painter and a novice with 3D in general. I'm trying to create simple cubes to learn the workflow from Blender to Painter and my expectation is that with UV maps and textures, whatever lays on top of the UV in Painter is what you will see in the output. So one square in the UV equals one side of the cube. What seems to be happening is that depending on the unwrap and padding I end up with steps or a cross showing on the output and either flat areas that weren't in the UV or streaks where the padding is attempting to make up the difference. (Probably way oversimplified) Auto unwrap is also unchecked.

I've include images so starting with a material I created in Substance (substance material.png) I create a 1m x 1m x 1m cube in Blender with no textures, apply transforms, and use Smart UV Project (unwrap.png) because even with manual unwrapping (blender mesh.png) I see missing seams highlights (missing seams.png) during bake.

After that, I have to scale down the bounding box (scale 2.png) to match my original texture otherwise the density(?) is off (scale 1.png). When I do finally export, I end up with the following normals which translate to my cubes as flat areas where the normal is flat. I've included two images based on the scale and the padding that was applied. (scale 1 padding dilation and diffusion.png, scale 2 padding infinite.png)