Maybe I found something.
New ‘Basic’ Level to keep it simple.
Drag in starter content couch.
Is this what you are seeing? Notice the spotty shadow
Then I turn off the visibility of the Volumetric Cloud.
Now the shadow is nice and crisp.
I have never looked this close before, I have been working more on gameplay and function, and I am pretty new to all of this as well.
Ok, Now you did it. So I place a cube in my open world and I get this.
After clicking through many options I found what may be obvious to some, was a setting on the cube called 'Contact Shadow". Which also has setting in the Directional Light as well.
Turning the Contact Shadow off(False) I get what I would expect.
One last one. In the ‘Basic Map’ I added a cube and I get no ‘contact shadow’ so maybe it has some more to do with light location too. Anyways, I noticed the shadow cast from the mannequin has blurred edge
which would be realistic but found that the ‘Source Angle’ in the directional light can make this shadow crisp edge.
Sorry for the ramble, but does this help?
I think now the crashing issue that you have is more of the priority. Which is probably another post.
Cheers