Which 2019 MacBook Pro? only the 16-inch can support DSC with 5300M or 5500M.
For 2020, the 13-inch with 4 Thunderbolt ports can support DSC (Ice Lake iGPU Intel Iris Plus Graphics).
AllRez should be able to list all the supported modes and tell you if the GPU supports DSC and if any modes include DSC.
If you have either of those, then try Catalina to see if it enables DSC.
If you have an Intel Mac with a GPU that supports DSC and the OS doesn't enable DSC, then a hack using OCLP, Lilu, and WhateverGreen might be able to make it work though I have not tested it.