Oh! Is it you just don't know how to access the camera in the hierarchy? In that case groups are a perfect way of doing this, they work very similar to tags in other engines.
@onready var playerCameraGroup = get_tree().get_nodes_in_group("PlayerCamera")
@onready var playerCamera = playerCameraGroup[0]
This is how I use groups quite often to access something that isn't a child which can get tricky, worth pointing out as well that in Godot you can use multiple groups on the same node, think of groups as a list, which is why you have to assign an individual variable a node from that list first before being able to use it.