If you enter a bunch of notes from a MIDI keyboard Dorico doesn’t have any option but make decisions about how to spell enharmonic notes. If you enter notes any other way, you get the spelling you entered.
MusicXML explicitly defines how to spell the notes, so if that is “undesirable” the problem is with the software that created the MusicXML file.
For tonality systems other than equal temperament, G flat and F sharp may not even have the same pitch. In Dorico they are not “different overrides for how to spell MIDI note 66,” they are “different notes”.