Is it possible to export base texture from unity terrain?

I know this question has been asked a lot, but no one has given helpful answer for it. I want to know if it is possible to export base texture from terrain, because I want to tweak it more in photoshop.

Some told me that you could achieve this through scripts, but I’m not that advanced in programming.

I don’t think so. The basemap is generated by unity itself from the assigned splat textures and (painted or scripted) splat weights. Even if you could read it somehow, you have no way to write it back.