Huh? I don't believe that is true, but explan further.

First, understand that for an airplane to right itself from a bank,
there must be a moment that rotates the aircraft around the
longitudinal axis. Therefore, the total lift on one wing must be
greater than the other. This extra force, times the moment arm,
creates the necessary moment.

The orientation of the wing lift to gravity is irrelevant.

When the aircraft sideslips in one direction or the other, there is a
component of the relative wind that moves parallel to the lateral axis
of the airplane. Due to dihedral, parallel to the lateral axis is not
parallel to the wing. When you resolve the vectors, you can see that
the sideslip creates a component of the relative wind perpendicular to
the surface of the wing, which increases its angle of attack. The
reverse happens on the other wing.

Most aerodynamics books contain detailed vector diagrams of this. The
FAA's material get this wrong, as does most aviation training
material. The point is, all dihedral effects depend on sideslip. In
theory, an aircraft in a coordinated turn should experience no
righting tendencies.