I have tried using tutorials and used the plugin RigEdit, and it seemed to work, but upon trying to use Animation Editor, it did not even detect the Root.
A picture of the rig joints would be nice as well but I believe the issue is that you will need a Humanoid instance or an animation controller instance under the same parent as the humanoid root part in order for the default animation editor to detect the rig. Currently I don’t see those instances in the model hierarchy or tree you gave. Or you could use moon animator which can detect the rig without those two instances I believe.