which of these are you using ADX for?
if its for the intraday gap, news, spike day-trading (hence scalping), then the delayed (multi-period trendline predictor) will not be as accurate as desired.
If its for a longer term, hence multi-multi-periods, then as a position trading indice, then it retains its worth.
The absolute best indicator for intraday trading remains "brain power analysis". It takes time to train this AI (and for some of us, our inteligence is truly "artificial") to wave patterns that are profitable. However, part of the make-up are these indicators such as ADX.
For example, take a 2min chart, 5min chart, 15min chart and 60min chart of the same security (irrespective of whatever it is), and then take a Tick chart (naturally this is less than 1min), depending on your processor and bandwidth speed, and you will see these patterns and do inteligent pattern recognition.
Perhaps this will help, and also, perhaps this will prevent this method from becoming "neutralized" as other indicators obviously have been...
Cheers