Your distance field shadows will ONLY come on between 20k and 30k units away. Below 20k, it will use CSMs. If you want to use your DFSs sooner, then lower the CSM range down. Personally, for outdoor scenes, I prefer to keep CSMs within 3 or 4k and use DFSs beyond that. If you would like to solely use DFSs, then set the CSM cascades to zero; to disable them.