I get this weird distance rendering of the terrain only on android standalone, while in editor or unity remote it works fine. Can someone give me an insight on what is going on ?
This is caused by mipmapping at a low angle. To improve the result you have to increase the anisotropic filtering on your floor / wall texture. There has been several similar questions
Anisotropic filtering is a special kind of mipmapping to improve the image quality when the image is sampled at a narrow angle. In Unity you just have to increase the “aniso level” of the texture in the texture inspector / importer.