Indeed, but before starting the monitoring, it would be good to evaluate past occurrences when the RTH -Buying weakened.
You can see that the RTH-Buying comes by waves. Each waves is initiated by a strong push (Blue trend lines,) whihc is followed by some sort of support line (Red trend lines). It would be interesting to tray to evaluate the S&P500 gains 3 days, 5 days, 10 days and 20 days after that red trend line is broken. If you get a negative return, then I believe that monitoring when the latest Red trend line will be broken makes sense.
Pascal