What is the best resources for 3D computer vision and SLAM ?

Hi, I have done some 2D computer vision such as classification, keypoints detection, gesture recognition, object detection etc. I want to delve into the realm of 3D computer vision.

Should one learn 3D computer vision or SLAM first ?

And for both, what is the best free lecture or online courses to follow with project ?

classification computer computer vision computervision detection etc free gesture recognition learn lecture object realm recognition resources slam vision