Instead of “trying” to raise an objection (a rather weak one, at that), why not take a pragmatic approach and try to come at this from a Trinitarian angle? The thing you say “defies logic,” really does no such thing at all.
You have two issues that intersect one another at a very critical point:
You impose your Unitarian worldview/framework back onto the Trinitarian when objecting to “Trinitarianism.” Thus, your Unitarian assumptions tend to “bleed over” onto other theologies. Your comments aren’t even an objection to “Trinitarianism,” per se. Rather, it is an objection towards a form of Unitarianism known as Modalism. The hidden presupposition underlying Modalism (like other brands of Unitarianism) is simply this: God is one sole individual.
Because you (being a Unitarian) think “God is one sole individual,” you impose that back onto me (a Trinitarian), when that is not what I believe. By doing so, you assume I (a Trinitarian) am a Unitarian, namely, of the Modalistic variety.
The difference between Modalism (a brand of Unitarianism) and Trinitarianism is that Modalism believes that “Jesus” pre-existed (in distinction from Trinitarianism) as the Father. That is, like all of their Unitarian counterparts, they believe there is one singular person in heaven, the Father. Hence, to them, Jesus is the Father. But for the Trinitarian, we do not believe that. We believe Jesus pre-existed eternally alongside the Father, thereby, existing in a “You,” “I,” “We” relationship. And that's where your issue is. You are conflating our theology (Trinitarian) with your Unitarian assumptions.
There are (14) instances in the Gospel of John alone, where some slight variation of the phrase πρὸς τὸν θεόν (Jn. 1:1b) is used. The number swells to (17) if we also include John’s Epistles. And if the Apocalypse is included, it swells to a whopping (19) occurrences.
This language (with some slight variation), is elsewhere used throughout the Testaments — including Acts 4:24, 12:5, 24:16; Romans 5:1, 10:1, 15:30; 2 Cor. 3:4, 13:7; Philippians 4:6; 1 Thess. 1:8, 9) — and another 20+ examples in the Genesis and Exodus accounts of the Greek OT (Gen. 17:18, 18:27, 18:31, 20:17, 24:49, 24:54, 24:46; Exodus 2:23, 3:11, 3:13, 8:25, 8:26, 9:29, 10:18, 18:19, 19:8, 19:21, 19:23, 19:24, 24:1, 24:2, 32:30). In each of these occurrences (aside from the occurrences where the neuter article τὰ is present), they explicitly refer to distinct individuals in some form of communication with one another.
In each instance (aside from the few that you would dispute, i.e., Jn. 1:1, 1:2, and likely 1 Jn. 1:2) there is real personal and numerical distinction. This is standard Johannine rhetoric when speaking of Christ’s decent/ascent to the heavenly places. Take Jn. 13:1-12 (Lexham) as an example,
Within the span of just a few short sentences, John uses such language (twice) in the immediate context to speak of Christ’s departing “to” God (and seven more times as the narrative progresses). But the reason for citing this example in Jn. 13 is not only to show the frequency in which John uses the language, but also the surrounding context in which it is used. There are conceptual similarities in Jn. 13 to the earlier Pauline work to the Philippians.
In Jn. 13, (and pay attention to the details of this) “knowing (εἰδὼς) He had come forth from God and was going away to God (πρὸς τὸν θεόν),” Christ rises from the table and lays aside His “outer garments,” clothing Himself with a towel (v. 4). In Phil. 2, Christ divests Himself of His glorious garments (vv. 6-7) by clothing Himself with human nature (cf. 2 Cor. 8:9).
In Phil. 2, Christ takes the form of a slave, yet, in Jn. 13, He performs a menial task often assigned to slaves (washing the feet of others).
In Jn. 13, upon completion of this task, Christ once again takes up His (former) outer garments. In Phil. 2, after His work on earth is finished, He returns to the visible glory with the Father that was His before time.
In Phil. 2, Christ is exalted by the Father and sits down (once more) on His heavenly throne, yet, in Jn. 13, Christ resumes His place at the table, from which He had temporarily departed.
The story in Jn. 13 is an example of humble service. In Phil. 2, Paul uses the incarnation and humiliation of Christ as an example of humble service (Phil. 2:1-5).
With the imagery and conceptual ties to Phil. 2 in the backdrop, John seizes upon language from his prologue (πρὸς τὸν θεόν) and weaves it back into the narrative to demonstrate that Christ will once more “resume His place at the table,” from which He had once departed (Jn. 1:1). He was “with” God in the beginning (Jn. 1:1, Phil. 2:6), and was now going back to God (Jn. 13:3-4, Phil. 2:9-11), seated at the right hand of God. But even more striking are that the words recorded in Jn. 13:3-4 are not the “spoken words” of Christ (or of the narrator for that matter), but even as the narrator explains, are the “inner-thinkings” (εἰδὼς) of Christ, which seems to form yet another connection to Phil. 2:6 in that both texts place Christ’s thoughts and contemplations on “equality with God,” which again points us back to the prologue, Jn. 1:1. Fresh on Christ’s mind was: πρὸς τὸν θεόν (Jn. 1:1, 13:3-4), which He then goes on to elaborate/reflect on (or, “speak His mind”) in the ensuing narrative (specifically, Chapters 14 through 17):
And it is this very language that is used when speaking about Christ’s return “to” God, pointing back to Jn. 1:1, πρὸς τὸν πατέρα.
It really is just that simple.