Not necessarily. While some movies claim to be based on true stories, 'Joy' could have a blend of real and fictional elements crafted to make an engaging narrative.
Yes, there are many films that can be considered 'joy films' based on true stories. For example, 'The Pursuit of Happyness'. It's a story about a man's struggle and his journey towards achieving happiness, which is inspiring and fills the viewers with a sense of joy in the end seeing his success.