This last Black Friday, I purchased a bunch of Udemy courses for Unreal Engine 4.  Mostly, I did it to give myself a kick in the rear to get going with this VR stuff.  I'm not terribly far in to the first course yet -- just warming up, really.  It's a beginner's course for C++ and I'm rusty, but still very competent in C++, so a lot of this is a refresher for me.  I'm happy with the pace of the course, the content, and the presentation.  Lots of it is super basic for me, of course...I've been a professional developer for a long time.  Still, I can recommend this one, so far.  And most of the concepts are going to apply in Unity, so I don't feel I've wasted my money by working on Unreal, but might still go back to Unity.