i used to use just the flip feature built into godot aka sprite.set_flip_h(true) but alot of my character bodies has adopted
scale.y = -1
rotation = deg_to_rad(-180)
else:
scale.y = 1
rotation = deg_to_rad(0)
i just havnt used it on uncentred animation, but sprite.set_flip_h(true) doesnt care for offsets or pivot points because it just flips the sprite, will have a play around with your method. im not very good coding or doing game dev, its just a hobby i take enjoyment in,
my salty attitude is only becasue i was waiting for an asset like this one. and want to use it in my never to be released project lol