I don’t hold to the patristic idea of synergism, at least as it is popularly conceived, because most work a contrastive view of agency (or a zero sum game). If it is 100% God, then it must be 0% human (and vice versa). If God exists outside the system, as supra-being, rather than another agent within the system, then you can have non-contrastive agency. Such that election is 100% God and 100% human, though the priority is always in God’s divine action and election. At any rate, that is my 2 cents on divine and human agency.
The Orthodox and patristic writers do not have the Augustinian-Pelagian controversy in mind and so are very pleased to use the terminology of synergism–fellow workers with God. Synergism is not Pelagianism. Synergism is not merely the independent agency of the human working together with the independent agency of God. Patristic writers affirm the full dependency as created beings upon God the Creator, who is the source of ALL life, ALL light, ALL wisdom, ALL glory, etc. To the extent that any creature experiences these attributes, they are participating in the grace and presence of God. As believers these attributes are displayed not merely as creational participation in the Creator, but as new-creational participation in the Creator-Redeemer. Accordingly, as believers partake in the life of Christ through the Spirit they are able to live–in the present morally and in the future with the resurrection. They do not somehow create this moral action or their resurrection on their own in some Pelagian manner. They only experience life through connection to the head who provides growth from God. You might disagree with their view of agency, but their agency must always be considered in this context.