It sounds like you are applying the noise on the “instances” position.
You need to realize the instances to be able to apply noise on the vertices/points of the instances.
Looking at your nodes, realize the instances after the “resample curve” of the instances and add the set position and noise there (before set curve radius - curve to mesh)
This is a really long thread and a complex setup, but you might find it helpful
The latest version is at the top to download.