How strong would the fuel rod and motor have to be? Since they are the only structural components it seems like they would have to bear the full thrust of the r

How strong would the fuel rod and motor have to be? Since they are the only structural components it seems like they would have to bear the full thrust of the rocket: The fuel rod is not bolted to engine, so the pressure in the combustion chamber is transmits the force upward. The motor must be attached to combustion chamber so the interface between the motor and fuel rod must counter all that force to keep the rod in the chamber.