What artist of the Renaissance was a self professed sculptor but was hired to paint the Sistine Chapel which was a backbreaking task for the artist?

The artist you’re referring to is Michelangelo Buonarroti. Although he considered himself primarily a sculptor, he was commissioned to paint the ceiling of the Sistine Chapel, a monumental task that he found physically and mentally exhausting. The project took nearly four years to complete and resulted in some of the most iconic frescoes in art history, showcasing his mastery in both sculpture and painting.