Doping is one of the most relevant paths to tune the functionality of cuprates, it determines carrier density and the overall physical properties of these superconducting materials. We present an oxygen doping study of YBa2Cu3O7-d (YBCO) thin films from underdoped to overdoped state, correlating the measured charge carrier density, nH, the hole doping, p, and the critical current density, Jc. Our results show experimental demonstration of a linear correlation between Jc and nH, up to Quantum Critical Point (QCP), due to an increase of the superconducting condensation energy. The ultra-high Jc achieved, 90 MA cm-2 at 5 K corresponds to a third of the depairing current, i.e. a value 60 % higher than ever reported in YBCO films. The overdoped regime is confirmed by a sudden increase of nH, associated to the reconstruction of the Fermi-surface at the QCP. Overdoping YBCO opens a promising route to extend the current carrying capabilities of REBCO coated conductors for applications.