I'm also having this problem. Sometimes I can recover from the freezes but most times its faster to crash to desktop and reload C:S. I've only been able to play these days by generally avoiding the use of Move It on roads, since I've observed that regular use of it is practically guaranteed to crash my game within a short amount of time.

Just occurred to me too twice.... 1st time, when adjusting rail bridges and replacing regular bridge with high speed train (from Content Creator Pack)
2nd time, after restarting previous game... while the freezes occured by the end of my session.And when exiting to main menu I got tnis error (from UnifiedUI ? )

The Mod C:\Program Files (x86)\Steam\steamapps\workshop\content\255710\1619685021 [UnifiedUILib.dll, MoveIt.dll, MoveIt.resources.dll, MoveIt.resources.dll, MoveIt.resources.dll, MoveIt.resources.dll, MoveIt.resources.dll, MoveIt.resources.dll, MoveIt.resources.dll, MoveIt.resources.dll, MoveIt.resources.dll, MoveIt.resources.dll, MoveIt.resources.dll] has caused an error [ModException]

Details:
System.NullReferenceException:
at (wrapper managed-to-native) UnityEngine.Component:get_gameObject ()
at UnifiedUI.Helpers.UUIHelpers.Destroy (UnityEngine.Component button) [0x00000] in <filename unknown>:0
at MoveIt.MoveItTool.DisableUUI () [0x00000] in <filename unknown>:0
at MoveIt.MoveItLoader.UninstallMod () [0x00000] in <filename unknown>:0
at MoveIt.MoveItLoader.OnLevelUnloading () [0x00000] in <filename unknown>:0
at LoadingWrapper.OnLevelUnloading () [0x00000] in <filename unknown>:0