The age of the ecumenical creeds appears to be a sustained war against Hellenism. Most if not all of the heresies that appear during this time are identified by the various Fathers who combat them as errors caused by Hellenistic thinking.
Docetism and Gnosticism are horrified by the notion that the divine could have any significant relationship with matter, so they reject the reality of the incarnation. This is Hellenism. Arianism and Adoptionism love divine transcendence so much that they can’t conceive of the divine getting messily entangled with the creation. This is Hellenism. Eutychianism and Monophysitism want to fuse the two natures of Christ in such a way that the human is radically denigrated. Major principles of Origenism are condemned at the Fifth Ecumenical Council as corrosive Hellenistic influences. Monothelitism continues the Hellenistic trend started by Eutyches, and is condemned for the same reasons.
On numerous points of theology the Church Fathers are quite aware of Hellenistic influences and expend great efforts to combat and overthrow them. Their war may not have always achieved its goals, and of course like anyone else the Fathers saw through their own eyes and had their own peculiar blindspots, but that they were aware of the enemy and fought it with all the weapons at their disposal is beyond doubt. To me, working from within a more-or-less Reformed tradition, this suggests the intriguing notion that the Church Fathers were quite good at locating and defending the antithesis. Huh.