All of the ModFactor algorithms (plus other ‘Factor categories) can be triggered / shaped by input level. Often, in two different places. Essentially, anything with a MOD SOURCE or SHAPE parameter. Set it to ENVLOP [ENV], or ADSR. SPEED will become SENSITIVITY [a critical adjustment parameter].
For control over delay time, the CHORUS (and, yes) FLANGER algorithms immediately come to mind. Adjust the MODFY DELAY O/P for the delay time in FLANGER. Crank the initial INTENSITY control. TYPE will figure very heavily into the final effect, as well.