You are certainly right that, compared to other aspects of creation in Blender, there’s a lot fewer tutorials on rigging that are in-depth and complete. It seems to be the thing that people want to do the least, and you’re far more likely to find tutorials on how to use rigging addons that do, or purport to do, much of the “hard work”.
That said, Mark Smith’s recommendation is spot on; and I would also highly recommend checking out a YouTube channel called DanPro which focuses on rigging, especially to achieve better/more realistic deformations in human characters.
