Took me a few days, but here it is:
Download:
custom_player_animation_11112020.zip
I made this public, so that anybody can make their custom player animation.
Yes, you need all of those symbols at once for animation to work properly.
I coded a simple custom action, which allows you to test your custom animation with a simple right-click.
Since the action doesn't have any facing directions, you need to rotate the camera with Q or E.