Start with Build and Deploy a React Native App (136 min, JavaScript Mastery), then Flutter Basic Training - 12 Minute Bootcamp (12 min, Fireship). All 493 lessons here are free, from the teachers' own official uploads. You'll need laptop stand, noise-cancelling headphones, second monitor and a few more basics (about $270 of kit). The book to keep beside you: Flutter in Action by Eric Windmill.