Are there any good animation tutorial?

I’m trying to make cutscene animations for my game. Animations are first-person (camera view = eyes view), so my amateur skills are enough to make them look kinda ok but still very stiff and unnatural
I did some researches in past, so I know basics: key principals from 2D, don’t animate every bone discretely with the same period, keep inertia, etc. But I have no idea how to put these rules in use, everything I try either makes it worse or don’t affect at all. I need tutorials on such basics, e.g. common techniques for inertia effect (I once saw a tutorial for making tail animations, so I assume there are such tutorials for a lot of things). But everything I managed to find is blender beginner tutorials or too irrelevant things like techniques for 2D

I’m not an animator, but once I was excited about and did some research. I found this video talking about animation principles:

Animation book: The Illusion of Life - Disney Animation.
And I also looked for some sakuga animation, which is pretty neat.

I just found this one, looks very promising: