The answer to this is not difficult. We should use the ECF as we use any other commentary. It is useful for study and instruction but must always be tested against the Scriptures. The Scriptures and Scriptures alone have the final say in all matters of faith and practice. The ECF did get things wrong, and often, they even contradicted each other. Scripture, on the other hand, has no contradictions. It is the perfect and holy words of God.
I have all 38 volumes of the Ante-Nicean and Post-Nicean Fathers, and have studied them extensively. They provide me with an insight as to what the Early Church believed. They range in value from the hot air expelled by Origen to the modern day solid Evangelical teachings like Tertullian. And for historical foundations and pillars of the Faith, Athanasius is my favourite, as the authority for the Canon of Scripture.
Once we get to "Saint" Augustine all bets are off. He lived in a fantasy world, and is the author of the pagan idea of original sin, and infant baptism, later adopted by Jerome, who declared that an infant who died without being baptised, i.e. sprinkled could
never enter Heaven!
So, just as today, there are a lot of diverse opinions out there.