Attached is a save file that, on my computer, takes almost 5 and a half minutes from pressing the load button to accepting input again.
I've also attached a debugger report that I attached for the full duration of the load, and it's telling me that over 80% of the work originates from "Component_CUSTOM_GetComponentsForListInternal", which unfortunately resides in UnityPlayer.dll.
The save was for a modded game, but the issue is still present with no mods enabled. I think this is due to the large amount of ladder building ghosts.
Load the attached save