Terrain that will run on older androids?

First off sorry if this is posted in the incorrect location.

So I have a project I have been working with that uses a Terrain object and it works fine for my phone. However it crashed when trying to load any scenes with Terrain on a cheaper phone running 5.0.

I wanted to test if it was something I had done to the Terrain that caused it to not work so I created a new project (Unity 2017.3.1f1 (64-bit)) added a terrain object and simple green texture and compiled it and it would still crash. Something to due with the opengl and gpu for the phone.

So I am looking to ether find a way to still use unity’s built in terrain system or find some other way to create simple terrain via the paint methods for height and textures that will still run on most phones.(basically I am worried since it still compiles and even loads the main menu scene, that the Google store will allow incompatible phones to download it.)

Found no information on terrain that will work with phones that I think are not compatible with ES3
(I still do not know excatlly why the terrain is not working on the other phone.)
However as for the compiling worries.

Unity - Manual: Android Player settings
Under Auto Graphics API
Important: GLES3/GLES3.1/AEP requirement is added to your Android manifest only if GLES2 is not in the list, and Minimum API Level is set to JellyBean (API level 18) or higher. In this case only, your application won’t show up on unsupported devices in Google Play Store.

So I am fairly sure this will prevent it from being installed to phones what normally would work but due to having terrain will not.