Can we paint plane as we paint terrain?

Hello everyone, hopw you all are fine.

I am new in unity so I dont know much term of this, so if I say something terrible then kindly ignore that!

I am making a top down game which will be running on android/ios devices. I used unity terrain and painted that with my textures. Now when i run it in my mobile device it is not smooth enough to be played.
I checked the FPS rate then it is showing 15 - 16 fps which was really low. after this i removed the terrain and used plane instead so the results was awsm, now fps is around 49 - 58.
Now i have to use plane in my game but the problem is that how can i paint that plane exactly like the terrain was…
I have attached the painted terrain.
Kindly give your precious ans and help me in this.
Regards Ikram

Well, you can write your own editor tool for creating textures but you said you are new.
so, my suggestion is; create a terrain with exact size of plane, paint it, go to top orthographic view at scene window, take a screenshot of that terrain, and use that image as texture for your plane. that;'s easiest way that came into my mind for now.

NorthStar79, its not working. because of resolution issue. my terrain is too big and when i take screen shot of it becomes blurry completely.
As we take screen shot so it isnt come up with high resolution, we adjust them manually.
My screen becomes blurry on mobile.

I think there should be a tool for this, like we take plane instead of terrain and then paint that plane and use it in our scene. it will be more effecient for mobile devices.

You should be able to run games using Unity terrain on mobile. You can try decreasing the resolution of the terrain. Also, you can paint a texture in programs like Photoshop (Or Paint) and apply it to planes. This will give the same effect, however, you’ll need to paint it outside of Unity and import it as a Texture.