Ls2023 Unfortunately, it is very difficult to determine the cause of your problem from this one image. One factor that comes to mind is that the skeleton's feet are not at the Y:0 coordinates on the Spine editor. What do the skeleton's feet look like on the Spine editor?

Ls2023 I have confirmed that this problem is reproducible with Spineboy and the default level. Unfortunately, we are not sure of the solution at this time, so I have opened an issue ticket here to investigate:
EsotericSoftware/spine-runtimes2510

You can subscribe to this issue ticket to receive notifications when there is any progress on this issue.

Ls2023 It appears that the problem with the distance to the shadow is due to the light settings.
The following image shows the DirectionalLight property, but with Shadow Bias set to 0.1, I was able to eliminate most of the gaps.

For more information, please refer to the UE documentation:
https://dev.epicgames.com/documentation/en-us/unreal-engine/movable-light-mobility-in-unreal-engine?application_version=5.3