Our previous study has been shown that treatment of coated conductors (CC) under high pressure - high temperature conditions can lead to further increase of critical current density especially in low magnetic fields [1]. Treatment under 100 bar of oxygen for 3 h of GdBCO_CC via Ag layer (which covered superconducting layer of CC) at 600 °C led to an increase in Jc (77 K, 0 T) from 2.57 to 2.67 MA/cm². The charge carrier density n_H(100 K) increased from 6.55´10²¹ to 6.91´10²¹ cm^-3, and  J_c(5 K, 0 T) =28.94 MA/cm² was observed after the treatment. The increase in J_c (77 K, 0 T) from 2.10 to 2.28 MA/cm² for GdBCO_CC which was oxygenated without Ag layer (etched by acid before oxygenation) was observed after treatment at 300 °C under 100 bar of O₂ for 3 h. In the both cases c-parameter of Gd123 decreased from 1.1735(1) to 1.1731(0) nm. The increase of critical current density is connected with overdoping by oxygen and thus by charge carriers of the superconducting GdBCO layer. Oxygenation under 160 bar pressure at 800 ^oC for 3h of tetragonal YBa₂Cu₃O_x film deposited on single crystalline strontium titanate substrate allowed to obtain critical current density J_c (77 K, 0 T) = 4.09 MA/cm² and J_c(5 K, 0 T) = 38.2 MA/cm². The value of Jc (77 K, 0 T) turned out to be twice as high as when saturated with oxygen under a pressure of 1 bar. As a result of oxygenation, c-parameter of YBa₂Cu₃O_x decreased from 1.1711(2) down to 1.1681(3) nm.  This work was supported in part by the funds from MICIU/AEI/FEDER for SUPERENERTECH (PID2021–127297OB-C21), FUNFUTURE “Severo Ochoa” (CEX2019–000917-S); MUGSUP (UCRAN20088) project from CSIC scientific cooperation with Ukraine; Catalan Government 2021 SGR 00440; and NAS of Ukraine Project III-7-24 (0788).