Procedural grass placement

Hello! I have a large terrain where I am trying to get a breath of wild style grass, kinda where the grass is so dense that it covers the terrain texture. I have tried using gaia to spawn terrain grass but it isn't anywhere near the density that breath of the wild has. I suppose that the built in terrain system will not support that amount of grass so maybe a geometry grass shader would work? I have no idea how shaders like those work, so are there like any examples out there for me to learn from? I tried googling it but all the examples don't work for such large sizes and they are too slow. Is this just not possible for unity, or am I missing something? I hope this isn't too much to ask. Any help is appreciated!