Steve Brunton, a University of Washington professor has a sweet lecture series called the Control Bootcamp that dives deep into control fundamentals while still being approachable. Great production values too: https://www.youtube.com/watch?v=Pi7l8mMjYVE&list=PLMrJAkhIeN...
This youtube channel has (seemingly good quality) Khan Academy style lecture videos on control systems, if you just want a quick introduction to the concepts.