In June 2020, Devon Rodriguez had 35 TikTok followers. He posted one video of himself drawing a stranger on the subway and woke up to 4.9 million views. Today he's the most followed artist alive. The backstory makes it better. He grew up in poverty in the South Bronx, started doing graffiti at 8, and got arrested at 13. The arrest pushed him into portraits. Drawing subway riders is a standard exercise art teachers hand out. His high school teacher assigned it to him in 2011, the same…