Basically, for some reason shadows always cause the game to crash, not much else to say.
Crash log:
Executable: I:\SteamLibrary\steamapps\common\GarrysMod\bin\win64\gmod.exe
-Lua Stack Traces-
Client
Not in Lua call OR Lua has panicked
Server
Not in Lua call OR Lua has panicked
MenuSystem
Not in Lua call OR Lua has panicked