It looks like the UV map of the mesh doesn't match the shape, or hasn't been formed. UV on a shape like a shoe can be tricky anyway, because it's not close to a cylinder or a plane or a sphere.

I'd suggest separating the mesh into Groups or Materials at the same lines where the real leather would have seams. The upper central section would then be a simple curved plane, and the wrapped part between the upper and the sole would be three nearly planar pieces. The seams are designed to allow each piece of leather to assume a one-dimensional curve, and they'd do the same for the UV.

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