The docs say:
However, the support for blending those animations via
AnimationPlayeris relatively limited, as only a fixed cross-fade transition time can be set. ( https://docs.godotengine.org/en/stable/tutorials/animation/animation_tree.html )
How do I do this sort of cross-fade with a fixed transition time using only the AnimationPlayer?
Godot Engine documentation
Introduction: With AnimationPlayer, Godot has one of the most flexible animation systems that you can find in any game engine. The ability to animate almost any property in any node or resource, as...