Is there such thing as a loose ball valve?
Typically, no. The tight clearance between the "ball" and the seats is what makes ball valves work so well. One with a larger (looser) clearance would be more prone to leak. While I'm sure that there are valves that require less force than others to actuate, this isn't a spec that I'm aware of that any manufacturer publishes.
The tight tolerances are necessary to keep the valve from leaking. I don't know of any way around it except leverage. Extending the lever will make it easier to turn. Of course, you'll also be doubling the travel. Maybe your unconventional application can accept the extra travel distance? The other alternative is to use a servo motor or solenoid.
You will need a valve operator to turn the valve. The operator is more complicated than the valve, so you buy both as an assembled unit. But you have to do your engineering to be sure that the service and conditions of the equipment match to what you want. And you have a bigger problem of power supply and controls for the operator. Most commercial grade plumbing supply houses have things like this.