In the modulation matrix, does anyone know a way to route modulation signals to the filter envelope amount? The Env Amnt is not listed as a modulation destination, but perhaps you know a work around? Modulating this single parameter would do magic to a few patches Iām working on 
I would like to modulate this parameter with the step modulator or other modulation sources.
I think many modulation sources and destination are missing and the mod matrix is quite limited within Halion 4 from doing some really complex things like you are noticing. I hope the mod matrix will be expanded in future updates.
In all fairness, I do achieve something close to the desired result when setting up Filter Envelope as Source, Cutoff as Destination and Step Modulator as Modifier in the Matrix. But then again I would like to control the level of impact of the modifier 
Steinberg can never win this 