Comparing constraints in a dynamical dark energy model with a constant equation of state (left-hand side panels) and in an effective description of an energy-momentum-powered gravity model as a dark energy model with an effective equation of state (right-hand side panels). Top panels: black solid curves show the one, two, and three sigma confidence levels in the two-dimensional plane, while the color maps depict the reduced chi-square. Middle and bottom panels: one-dimensional posterior likelihoods for the matter density and the relevant equation of state parameters defined in the text.