I am sure that it would be fairly easy to get some air, gas or electric piston parts that simply presses that compression bag on a fixed cycle. You wouldn’t need 1:1 personnel but you would need someone keeping an eye to make sure they were functioning continually.
The compression bag isn’t all that robust for long term usage. They are often tossed after a (relative) few uses in ambulances.
You also need to have a tight seal around the face to prevent leakage. Most importantly, the head needs to be held properly with the jaw thrust open to ensure that the air goes into the lungs, not into the stomach. Good try though
There are plans online to build your own ventilator by using a 3D printer to make most parts, supplemented with some electronics, and downloadable code. The creator posted warnings that it is use at your own risk and is only meant to demonstrate that they can be built at home, but you should use medical facilities. Video of it is impressive.