Complex sentence: He wanted to be an artist, filmmaker, or illustrator, but he was discouraged by societal norms of Japan which favored finding safe, well-paying jobs and because his uncle was an artist who suffered from financial difficulties.
Split into simpler sentences: He wanted to be an artist or illustrator, but he was often discouraged by societal norms of Japan which favored finding safe, well-paying jobs. He was also discouraged because his uncle was an artist who suffered from financial difficulties.