I’m looking for a single word or short word group that describes doing the right thing for the right reason, or a person who does the right thing for the right reason
A word that describes doing the right thing for the right reason is, from Lexico
1 The quality of being honest and having strong moral principles.
a gentleman of complete integrity
A word that describes a person who has integrity, also in Lexico, is
1 (of a person or their behaviour) acting in accordance with morality and showing recognition of right and wrong.
a principled politician