>>5733414I think you would just use "artist". It is a both general and specific term. Salvador Dali was like you said, a painter, film maker, and author and is referred to just as an artist. Renoir did painting and sculpture, and is an artist. Felix Vallotton as well was a printmaker, illustrator and painter... just an artist.
I think being skilled in multiple disciplines is much more common in art than it is in the branches of science and mathematics, so there is no special term for it. Artists are expected and encouraged to experiment and branch out into other fields, though they usually are only well known for doing one.