I'd agree with Tushar's suggestion. Use a calculation stage to extract the collection up to the dynamic number, such as [col_JSON_Data.data.results.JSON:Array] and store that into a new different collection. Then you can loop through that new collection if needed and you can get data out of the fields by using the object 'Utility - Collection Manipulation' with the action 'Read Collection Field' which lets you dynamically specify the Field Name.
Edit: Reading your post again, it occurs to me that part of the issue is that it looks like you're actually trying to get a collection instead of a specific value even at the bottom of the hierarchy of nested collections. I'd say just use Calculation stages in order to extract nested collections, and that should get you what you need even if it feels a bit clunky.
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Dave Morris
Cano Ai
Atlanta, GA
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Dave Morris, 3Ci at Southern Company