I managed to snag the Udemy course 'Modern React and Redux' when it was on sale recently. The course is presented by Stephen Grider and I found it to be a comprehensive introduction into both the coding and the reasoning behind the way react/redux is coded.
I was impressed with the way that Mr Grider presented that, having completed the course, I enrolled in a number of his other courses.
Udemy seems to have sales periodically, so it's worth checking back now and then if the course you want is currently full price.