In its most general form, UNNEST can take several arrays as arguments, and it can produce an additional column to reflect the order imposed by the sub-indexes.

If you wrote out each of these sub-tasks separately, creating a procedure manual for each of your use cases would simply be a matter of assembling the sub-tasks in the right order.

This example serves to illustrate the importance of understanding a product at the level of its sub-systems, in order to prevent complex failure modes leading to costly product recalls.