When i open a new raw file (form my canon or sony camera) from adobe bridge cc 2019 to camera raw cc 2019, my default seetings that i previously reset and save, changed. The changes append in the détails menu(tab). I like my setting to be all a zero state, but the amount sliders, the detail sliders and the noise reduction sliders just been move. see pictures.
Custom defaults are specific to the camera model which was used to make the active image at the time of resetting. So if you want new defaults for both the Canon and the Sony, you will have to save them twice.