Minimum-volume conjecture for spherical knotoids

A spherical knotoid is a knotoid in $S^2$ whose associated hyperbolic complement has a hyperbolic volume. The knotoid $2_1$ denotes the spherical knotoid with the indicated two-crossing label.

Minimum-volume conjecture. The unique spherical knotoid of smallest volume is the knotoid $2_1$, and its volume is approximately $5.33349\dots$.

This conjecture identifies the smallest-volume spherical knotoid and gives a numerical estimate for its volume. The supplied text does not state whether the claim has been proved or disproved.