I don't have any boot animation option in my themes app in the customize theme section whereas many others have that option with them.

I want to add my own boot animation to my phone but i am unable to do it because there is no option for changing the boot animation.

My specs:
MIUI 12.0.1 stable version
Android 9
Redmi Note 6 pro

Kindly give me an option of boot animation or suggest me how to resolve this problem.