In the six years since the discovery of the 125 GeV Higgs Boson, the ATLAS and CMS experiments have collected pp collision datasets unprecedented in terms of both energy reach and statistical power. These data have already confirmed many of the SM’s key predictions for the 125 GeV Higgs boson’s intrinsic properties and couplings to the W/Z bosons and third generation fermions. However, the experimental investigation of the boson's couplings to the first and second generation fermions remains comparatively unsatisfactory. For example, such is the success of the LHC Run 2 Higgs programme, the Higgs boson decay to charm quarks now represents one of the largest expected contributions to the total Higgs boson decay width for which we have no experimental evidence. I will begin by reviewing the latest ATLAS results on measurements of the 125 GeV Higgs boson and outline the "state of the art” in our experimental understanding. I will then proceed to discuss the latest ATLAS efforts to advance this frontier towards elucidating the Higgs boson’s couplings to the first and second generation fermions, with a particular focus on the charm quark.