universe is rightfully called the standard model of cosmology, after having successfully passed a broad range of tight observational tests [@Eisenstein:2005su; @Percival:2007yw; @Percival:2009xn; @Kazin:2014qga; @Spergel:2013tha; @Ade:2013zuv; @Ade:2015xua]. This model augments the cosmic baryonic and leptonic matter components in the Standard Model, with two additional ingredients that dominate the cosmic energy budget, cold dark matter (CDM) and a cosmological constant, $\Lambda$, with the latter playing the role of vacuum energy that is responsible for the observed late-time acceleration. Central to the above paradigm is also the assumption that gravitational evolution is governed by Einstein’s General Theory of Relativity (GR), which led to the observed inhomogeneous pattern of the Large-Scale Structure (LSS) of the Universe through the process of gravitational instability. The value of the vacuum energy predicted by quantum field theory, however, is orders of magnitude larger than the best-fit one that is necessary to explain cosmic acceleration, so $\Lambda$ needs to be fine-tuned; the so-called cosmological constant problem [@Weinberg:1988cp]. Such an unfortunate mismatch, together with the need to fully explore the space of all theoretical alternatives, has generated growing interest in testing gravity models that self-accelerate though a large-scale modification to GR, instead of dark energy, the so-called Modified Gravity 