[Question] Why should someone do the MOST good? Does a normative argument even exist?

I’m sure you’re busy so I’ll cut right to the chase. Can you please let me know:

  • if there is a good reasons why someone should try to do the most good?

    • Or good reasons why such normative arguments shouldn’t be attempted?

P.S. This is not same question as “why should someone should be altruistic?” Rather this is asking if/​why someone try to do the most effective altruism possible i.e. they should not compromise altruism with any competing motivations.

P.S.S. I’ve searched for hours and was unable to find any such normative arguments online. So I could really use your help.