Question Animation Rigging: Foot IK Correction

While I generally love the new Animation Rigging package, I've yet to figure out how to actually use it for foot correction. Yes, I understand you can use the two bone constraint to move a leg/foot around, rather I'm talking about the typical use case of modifying an existing custom animation with IK to place a foot correctly (on a slope etc).

Effectively I want to "keep" the custom animation, but offset it by a programmatic amount (raycast to ground, set an IK target there). What's the best constraint/method to use with the Animation Rigging package for this purpose? I couldn't find a single tut or doc on it, everything just shows you how to use the arms in the most basic way. Thanks!