Continuing in the מאמר, the רבי analyzes the אלטער רבי's descriptions of the King's Presence in the field, uncovering Hashem's involvement during אלול in two ways: Reciprocal, and Core.

How does that work together with what we know about אלול being about our עבודה?!

This is the חידוש of the מאמר: The relationship of Hashem and אידן in אני לדודי is not about the עבודה of the אידן, it is about the very existence of אידן (which is expressed in their עבודה)!