  In this Letter we construct the Hubble diagram for a Universe where dark
matter is universally charged under a dark non-linear electromagnetic force
which features a screening mechanism of the K-mouflage type for repulsive
forces. By resorting to the Newtonian approximation, we explicitly show that
the cosmological evolution generates an inhomogeneous Hubble diagram that
corresponds to a curvature dominated expansion at short distances and converges
to the cosmological one of $\Lambda$CDM. We discuss the potential impact of
this inhomogeneous profile on the Hubble tension. For completeness, we
explicitly show how the Newtonian approximation can be derived from an
inhomogeneous relativistic Lema\^itre model.
