The important point is that Dorico identifies accidentals by pitch delta rather than by glyph, and this is a good thing. You’ve noticed that when you change the tonality system of existing notation with accidentals, some or all of them may disappear – they are still there and functioning the same in terms of pitch, just invisible, if they are not defined in the current system.
See this recent thread about an easier method for retuning existing notation, and some issues working with tonality systems.