You should know BSM wasn't validated for the last 50yrs ,it is been used despite being wrong at 0-DTE.
Practitioners know it is broken,they inflate implied volatility to compensate
As for GCM, I'm claiming it's a better theoretical model for short dated options with real data
Black-scholes has been stress-tested for 50yrs across billions of trades and we have validation for gamma capture on one year of instruments and you're wondering why it should be trusted?