Terrain textures makes game slow

Hi, I have a top down game with normal stats: 24 SetPass calls, 127.2k tris, 182.1 verts. When I paint my terrain with textures the whole game becomes very laggy on mobile devices (around 5 fps).

It becomes better when I change the base map distance to 0 (so that the whole terrain is a 2048 resolution texture) but that is very ugly for a top down game because rock- and stone textures become very pixelated. How can I make my terrain faster while avoiding pixelated textures? I'm using around 7 textures total.

Is it better to make my terrain in Blender and then import it into Unity or...? I have changed everything for the texture settings but my game is always slow except when I put the base map distance to 0.

Thank you!