Topological sliceness and ribbonness conjecture for even 3-strand pretzel knots

Let $K$ be an even 3-strand pretzel knot, meaning a pretzel knot with an even parameter in the relevant parity convention. Topological sliceness and ribbonness conjecture. Then $K$ is topologically slice if and only if $K$ is ribbon.

The conjecture would complete the characterization of topological sliceness for even 3-strand pretzel knots. The paper proves the equivalence except possibly for the family excluded in its even-pretzel theorem; Lecuona's proposed obstruction for that family would imply this conjecture.