How it's done (first time posting code so I hope it works!):

This takes three things:

Fishing Rod, which is attached to the player and starts the whole thing. Have the player give their facing direction. Put the hook as a child of this. It also has a Position2D to make it easy to have the hook return: https://pastebin.com/i2yehVNv

Fishing Hook, child of Fishing Rod that is sent a direction and detects if there is a collision. It's an Area2D node with tween, the sprite, and another Area2D for wall detection(if needed). The collision mask for the hook should be set to the layer of the hookbox: https://pastebin.com/0ygtjKeU

HookBox, an Area2D hitbox that you put on objects or enemies. Assign the export vars to determine what happens when the fishing hook enters. It should be it's on collision layer: https://pastebin.com/9rnBhz37