You can just about play entire quests of girls that do not corrupt you and not lose any loyaltycan i do nothing at all for the loyalty quest? like no go to any placeand be at home and no interaction with anyone?
One of the examples being Zoey or Kimiko , they aren't affecting your loyalty and are indeed girls Kiara would approve instead for you to be with.
However duly note in future if you do keep going , despite your loyaty staying good you won't continue the story as you'd go in that specific girls canon story instead.
So yes , be nice and kind and etc all you want but there are specific points that once reached will not let you progress the "canon main story"
For that you remain fully loyal and zero corrupted.