Question How to import custom terrain paints?

Hello all,

I've been trying to track this down for a few days and maybe I just don't know the right tools/words to use. I would like to create procedural terrain paints in blender and then import them into unity and paint them on my map.

Ex. I have built the map in unity using the terrain tools. Currently the "rock" textures, even the ones from the asset store aren't what I want, so I would like to import one I created from blender. So far everything keeps redirecting me to the asset store/tutorials on how to use the unity painter tools, but nothing for custom content.

So far, I have tried baking the different maps (normal, diffusion, roughness) in unity and importing those into unity; but the diff map doesn't wrap correctly (it is on a sphere, and looks like it is just putting a screenshot of the diffusion map onto the sphere). So then I tried importing it as a .blend and then .fbx file, but everything was grey and there was no texture. Even after trying to "extract materials".

Obviously there is a way to create useable terrain paints since they are on the asset store; I tried looking though the asset documentation but could not find anything that specifically states the requirements such as needing a script, file format, or anything. Can anyone point me in any direction so that I can create my own assets and use them in unity?

I have read on some obscure forum post that terrain paints have to be generated in unity with no additional details, so if that is possible, how does one go about doing that & maybe I can skip blender all together.

-E