Raytraced distant field shadows on large/far objects

hello folks i’m having trouble on a scene.

i have a tower and cartoony clouds wich are two very big assets viewed from a long distance in my scene ,
problem is: shadows.

using CSM and setting it for a long distance works well but everythings else near my camera looks very poor…

and if i do the opposite i have no more shadows on my clouds and tower.

so i’ve tried using raytraced distant field shadows wich gave me nice results on my trees but not on my clouds and tower since they are two big objects and RDFS seems to fade out when i scale an object up:

any ideas ?