toggle rigidbody constraints?

I am going nuts with this elevator thing. I can only get the player to ride it is if “Is Kinematic” and “Y constraints” are unchecked. But then the player just is a mess in the world randomly changing heights. I have tried to play with gravity thinking that would solve it but no. This is the Ethan Character from the Stealth tutorial and I have the same settings as the tutorial.Is there anyway to toggle theses settings on the fly? I tried to make the player a child of an empty game objects to access those variables in an animation( since player itself is read only). Kinematics enabled was an option but there was no animation channel for the constraints

The way rigidbody constraint toggling works is a little weird; here is a decent explaination:

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