You’re describing someone who believes it is beneficial to look unselfish but not be unselfish.
If you are selfish, but have reasoned out that helping others is the correct goal to have, you would believe not that it is beneficial to look unselfish, but that it is beneficial to act unselfishly. And if you believe that but do not alieve it, System 2 would look for ways to do unselfish things that System 1 would perceive as selfish, so as to better motivate yourself toward those goals.
You’re describing someone who believes it is beneficial to look unselfish but not be unselfish.
If you are selfish, but have reasoned out that helping others is the correct goal to have, you would believe not that it is beneficial to look unselfish, but that it is beneficial to act unselfishly. And if you believe that but do not alieve it, System 2 would look for ways to do unselfish things that System 1 would perceive as selfish, so as to better motivate yourself toward those goals.