Although maybe not with as much detail as you might be, I’m of course aware of the historical evolution of concepts in relation to Plotinus’ the One and the Abrahamic (in many a way, biblical) notion of God—whereby the two otherwise quite disparate concepts were converged, tmk not by the Neoplatonists but by Abrahamic philosophers.
There more back and forth than is commonly realized. Jewish and Christian Platonism was already well established in Alexandria generations before Plotinus (e.g. Philo). The great early Christian scholar Origen was an older contemporary of Plotinus and it's not implausible that they were in the same circles since there were only so many educated people, even in a larger city like Alexandria.
A lot of Plotinus also seems quite similar to Gnostic Christian theology that was popular in Alexandria both prior to and during his lifetime. Unfortunately, we don't have much exact history to go on here so it's unclear if these ideas were just "in the air," or if Plotinus specifically borrowed them and then attempted to reify them and remove the specific Christian and Jewish context. Certainly though, the different strains of Platonism being discussed in the city had to influence each other over the years. In many ways the triumph of orthodox Christianity was also a triumph of a certain brand of neoplatonism over competing gnostic and "pagan" forms.
If (1.b.), then SD is governed by at least one telos which SD deems worthy of fulfilling (i.e., deems beneficial and thereby good). Because it is a telos (which SD understands as good), this strived for end cannot be yet actualized by SD while SD holds it as intent and thereby purposefully behaves. Moreover, and more importantly, this intent via which SD behaves purposefully cannot have logically been created by SD for, in so purposefully creating, SD will necessarily have yet been striving toward some telos (a yet unactualized future state of being) which SD deemed to be good. A purposeful SD will hence, logically, at all times be moving toward that which is (deemed to be) good without yet having actualized it as SD’s intent/end—a moved toward intent/end which is logically requite for SD to create anything purposively (very much the creation of so termed “everything”) and, hence, which cannot be the (purposeful) creation of SD. Hence, in (1.b.) one then logically obtains the following necessary consequence: SD is forever subject to (and constrained by, hence limited by, hence determined by) an intent which SD deems good which SD nevertheless in no way created.
Unfortunately, I think this is really misunderstanding the Christian tradition. It's premised on violations of God's eternal nature, divine simplicity, the Doctrine of Transcendentals, and really the Analogia Entis as well.
God can't be striving towards things "before and after." God is absolutely simple, not stretched out time. The whole of God is always present to God's self (divine simplicity implies eternal existence, "without begining or end," not simply "everlasting.")
Goodness is a transcendental property of being along with Truth, Beauty, and Unity. But God is being itself— Deus est ens—and in God (and only in God) is existence part of essence—Ipsum Esse Subsistens. God
is goodness itself.
You're proposing a sort of voluntarism that I think will only make sense in a sort of post-Reformation frame where the Neoplatonic assumptions of the Patristics are intentionally stripped out, the univocity of being is asserted, etc. I think they would be more than happy to agree with you that their God is not "the God of the philosophers," but this itself is a radical break from the Patristics tradition.
Moreover, they would would deny the existence of TD since the Good is defined purely in terms of God's unfathomable will. But such conceptions are decidedly modern.