I have continued my diagram into vv. 5-6. There are a lot prepositional phrases. I believe “In love” “to adoption” “as sons and daughters” “through Jesus Christ” “to Himself,” “according to the good pleasure” “to the praise” are functioning adverbially and are modifying “predestined” as they answer the adverb questions “where?” And “how” (see diagram below)
I additionally I diagramed “with which He favored us in the Beloved.” to show it modifying “of His grace,“ at it makes the most sense theologically (ie its through the Fathers grace that he has favoured us in Christ“ hopefully my logic here is sound.
