You are so wrong.
At the Constitutional Convention, Northern states insisted that only free persons be counted for the purpose of apportionment of members in the House of Representatives. Southern states insisted that all persons residing within a state be counted for the purpose of apportionment, whether they be free or slave.
The 3/5 Compromise was just that: A Compromise between the Northern insistence that only free persons be counted and the Southern insistence that all persons be counted.
I’m sorry that you cannot see the hypocrisy of the south’s insistence on including slaves “for representation” when they were denied representation. In doing so they only postponed the inevitable confrontation between Freeman and slaveholder.