The strict Borel reducibility conjecture for positive-rank torsion-free abelian groups

Let $\bigsqcup_{n\geq 1} \cong_n^+$ denote the disjoint union of the isomorphism relations $\cong_n^+$ on the corresponding spaces of torsion-free abelian groups, and let $E_\infty$ be the universal countable Borel equivalence relation. The strict reducibility conjecture.

$$\left(\bigsqcup_{n\geq 1} \cong_n^+ \right)<_B E_\infty.$$

This asks whether the combined classification problem for these groups is strictly below the universal countable Borel equivalence relation, extending the analogous result for torsion-free abelian groups without the positive superscript. The source gives no resolution.