I had the same issue with my landscape. Dynamic lighting did a good job on some of the terrain, but very pixelated like textures appeared on back side of slopes. Dirty botches of low resolution “shadows”. The only way I managed to mitigate it is to increase the landscape resolution mainly Using “Resize mode: resample” and picking 2*2 sections per component in the “Landscape” mode. After that I just started smoothing things until these “Shadows” smeared away. Not sure if this is the “correct” process but It did a better job than tweaking the “Shadow bias” and “shadow slope bias” and the cascades. Hopefully it will help someone.
