For what it’s worth, a personal anecdote: Nearly 20 years ago, when I was a very new Catholic, but not so old person, I had an urgent spiritual need that I took to God in prayer–more like pleading for help. In those days God seemed to be teaching me many things directly. I’ve seen this with other new Catholics, as well. They seem to be full of insights and personal awakenings. Later on we are expected to walk more by faith within the grace of God even if we have no such experiences. Anyway, I begged the Lord for help and heard him tell me (I understood it as a teaching moment) to go to Mary. So, I made my case to her, and she, also as a teaching moment, told me to ask St. Michael for his aid. I did so and got immediate relief.
It put me in mind of Daniel (chapter 10) praying and praying and seemingly getting no answer until the Angel of the Lord appeared to him and told him he had been delayed by the forces of evil and had called on St. Michael to help him. I saw then that God uses us all, men and angels alike, for his purposes.
So, those in heaven, be they the saints or the angels, are simply doing God’s will. Therefore, to ask if praying directly to God or through the saints is more effective is really asking if God is still God and working his will if he acts directly or through an agent. The answer is yes.