Here is what I did:
The bounds Scale parameter on static meshes seem to directly affect the distance at which an actor’s shadow is culled.
To optimize the time it would take to do this manually for all actors, I created a blueprint that changes the bounds scale of all static mesh actors in the scene when I run the command. It is VERY simple and effective.
THE RESULT:
before vs after
P.S. Other commands like r.Shadow.RadiusThreshold and r.Shadow.FadeResolution had absolutely no effect for me in unreal 5.3, so this was the only option that actually had an impact.