SetParent" to move the parent and child of the object without a charactercontroller, but if a charactercontroller is attached to the object, the object falls without moving the parent and child.
However, if a charactercontroller is attached to the object, the object will not move and will fall.
This is an addendum.
I recreated a new project with the minimum configuration. The parts I was using are still there.
I have zipped the project file in the following page. If you can take a look at it, please let me know.
https://firestorage.jp/download/483c6e64f7fc36f536d971df2f2ca914e4b77e59