Seeking advice for Foliage in the distance....

I am in the process of optimizing an open world with a very amble foliage and a very large 16x16 map, I do not use world partition. I am looking for a way to generate a hlod for the foliage, a mesh for far distances that is very light, currently I have set nanites with preserve area and cull distance 0 for the plants that have more visibility, all others have a cull distance from 10000 to 30000, the problem is that the performance is still worrying, I have no way to include in hlod the foliage, does anyone have any advice?