int _0xF2CA003F167E21D2() // 0xF2CA003F167E21D2 0x106C8317 b323
BOOL _LOADINGSCREEN_GET_LOAD_FREEMODE() // 0xEF7D17BC6C85264C 0xD87F3A9E b323
void _LOADINGSCREEN_SET_LOAD_FREEMODE(BOOL toggle) // 0xB0C56BD3D808D863 0xC0B971EA b323
BOOL _LOADINGSCREEN_GET_LOAD_FREEMODE_WITH_EVENT_NAME() // 0x8AA464D4E0F6ACCD 0x94BCAC7C b323
void _LOADINGSCREEN_SET_LOAD_FREEMODE_WITH_EVENT_NAME(BOOL toggle) // 0xFC309E94546FCDB5 0x7D90EEE5 b323
BOOL _LOADINGSCREEN_IS_LOADING_FREEMODE() // 0xC6DC823253FBB366 0x734CFEDA b323
void _LOADINGSCREEN_SET_IS_LOADING_FREEMODE(BOOL toggle) // 0xC7E7181C09F33B69 0x8C227332 b323
void _0xFA1E0E893D915215(BOOL toggle) // 0xFA1E0E893D915215 0x5C350D78 b323
Experimenting with these Natives is probably a good starting point for you. No documentation on what they do so all you can do is try each and see what happens.
I would assume that _LOADINGSCREEN_GET_LOAD_FREEMODE will provide a true/false if the game is loading, which you can continuously check, then run the rest of your script as soon as it ticks to false.
The real question here is though, why do you need to wait for after the loading screen? Why not just run the script immediately?