Regarding your requirement to “inject” force on one side only, you are asking the impossible. For any static system to keep from accelerating out of control, the summation of forces in any direction has to be zero. There is a very real reaction force at the restraint.
In free body diagrams for science or engineering, the applied forces are treated no differently than reaction forces that balance them out. If you apply 1000 lbs at one end of rope, the other end will also have to apply 1000 lbs to stay balanced, and it makes no difference if this balancing force is applied by a weight, an immovable object or a mechanism.
I know for some, this isn’t intuitive. Even the act of standing on the ground means that the ground must push up on you equal to the force of you pushing down on the ground, or you will sink into the ground until the forces balance out.