How to simplify(decimate) mesh of generated terrain?

I have a generated planet, it is divided into many chunks. I need the chunks that are in the distance to be of poor quality. I want to optimize the mesh in the distance. I have tried many different assets and they all create artifacts in my chunks and mess up their borders. Please tell me how to reduce the number of polygons in the mesh in the form of a generated chunk? All generation taken from here: https://www.youtube.com/watch?v=vTMEdHcKgM4&t=598salt

screenshots: https://imgur.com/a/PIEXlR7