My Alesis Andromeda has variable slope shapes for it’s envelopes, 3 types of Exponential, linear, and 3 types of Log, setting per stage.
Since then the only synth I bought was a Hydrasynth Explorer, which also has continously variable envelope slope shapes, also per stage. So I presumed all modern synths had such a feature.
Sadly the Polybrute does not
So requesting such a feature