For your second example it's impossible to find a YouTube video of Chika dance that is available in every country. Try this: https://streamable.com/0hrdh

It's remarkable how smooth the animation is. And how natural the character's movements are. This scene jumps over the uncanny valley straight into being enjoyable.

And I think there's an AI paper from a Chinese researcher using this video as a demo.

Correction. The actual Kaguya-sama link is this one:

https://www.youtube.com/watch?v=eqjFmsZGBSc

Second link is the same as the first.