[Perhaps habitually, and for several reasons], I try to avoid thinking along a single-line scale, with Pelagian toward one end and Calvinist toward the other. [One is my desire to avoid] any implication that the truth is somewhere between them. I just think that the truth is the standard, and [it] is not on any line nor held in any creature's mind. Everything else tries to arrange itself positionally according to that, and I don't see much value in arranging myself in relation to anything but the truth.
If we accept your premise that the truth is not on any line—which I believe, too, by the way—then what could explain your reluctance to identify your view with either Calvinism or Reformed theology (hereinafter "Calvinism")? After all, I share your perspective on truth, and yet I don't see any difficulty in using such labels, provided they are qualified as needed—for
Calvinism is a locus, not a line. And the question regarded Calvinism, not a spectrum between Pelagianism and Calvinism, so I don't see how avoiding such a label is supposed to guard against the implication that the truth lies "somewhere between" Pelagianism and Calvinism, especially since (a) the truth isn't located on a line anyway, and (b) nothing in the original question suggested a spectrum in the first place.
I think we also need to distinguish between rejecting relativistic scaling (and the notion that truth is assumed to be "in the middle") and rejecting all conceptual frameworks that involve positioning doctrines in relation to each other. I stand with you regarding the former, but I take strong exception to the latter. One should not throw out the baby (the utility of theological categories) with the bathwater (some artificial third way in a false dichotomy).
So, even though I genuinely wish to understand, I still find myself wondering what explains your reluctance.
That being said, the spectrum from Pelagianism to Calvinism exists because these loci map real, substantive differences in how we understand sin, grace, agency, salvation, and so on. It is not something arbitrarily made it up. It is an integral framework born out of substantive debates in church history, forged in the fires of councils and cast into confessional standards. These are not merely "points on a line," they are comprehensive systems of thought with distinct presuppositions about human nature and divine action. It may sound humble or truth-centered to say, "I don't place myself on that scale," but any set of substantive beliefs will inevitably align more closely with one doctrinal locus than another. There is no escaping the fact that doctrine has structure and implications. Either grace is monergistic or it is not. Either the will is enslaved by sin or it is not. Either election is unconditional or it is not. Whether you wear a label or not, you're standing somewhere.
As for your claim that the truth "[is not] held in any creature's mind," has the Lord not spoken? Has he not revealed truth to creatures? Is the Holy Spirit not the Spirit of truth, guiding us into all truth? Then yes, the truth is held in creaturely minds—not exhaustively, but truly. God has revealed truth in his word, and he has gifted the church with teachers who labor to understand and confess it.
The labels Calvinism or Reformed theology are not meant to be the final word. They are shorthand for a confessional tradition that is seeking to align closely with God's revealed word. To reject those terms without a clear articulation of what you do believe tends to result in theological ambiguity, not fidelity to truth. Don't fall into the trap of thinking that escaping theological categories is the same as being faithful to the truth. God gave his church teachers, creeds, and confessions for a reason. We use these tools not to replace scripture but to guard and articulate what scripture teaches. The labels matter because the truth matters. That is why the Reformers risked their lives to confess them.
Therefore, rather than eschewing loci within a spectrum, I would encourage you to clarify your position relative to what the church has historically confessed. We all arrange ourselves in relation to something, whether that is scripture, tradition, reason, and, yes, the categories others have developed in pursuit of doctrinal clarity (e.g., trinitarian). The key is to ensure that such categories remain subordinate to the word of God, not abandoned altogether in the name of independent thinking.