optimized grass for huge landscapes used in high altitude animation shots

Hello everyone,
I need to create a very large landscape. the landscape consist of huge rolling grass fields. the size of the environment will be about 50 miles. the purpose of this environment is to be used as background environment for an animation video of a battle. and the shots are of fighter jets fighting in the air. what is the best way to add grass in this scenario? as the environment is very big so it needs to be optimized and also the shots are from a high altitude so there should be no visible tiling and also the grass should be visible from far away.
what can I do in this situation?
I’m new to ue5 so I cant figure out how to handle this situation