You could simply put a CSV on the well pump. When the pressure switch starts the pump, the CSV will adjust the output of the well pump to match the rate you set at the flow control gate valve. So the pump will draw a steady 3 GPM from the well while you are filling the storage tank at 3 GPM. The water level in the well will remain constant, instead of going up and down like it does when the pump is cycling.
But it would be simpler to just put a 3 GPM Dole valve on the well pump, (or use the gate valve you have now), and let the float switch in the storage tank turn the well pump on directly. No pressure tank, no pressure switch.
When you restrict the pump with a valve, the amperage drops about 30%, and the Symcom sees that as a dry well, and shuts the pump off, even though it shouldn’t. If you adjust the sensitivity for the Symcom to work at the reduced amperage when the pump is restricted, then it shuts the pump off on overload when you go to full flow. With a 3 GPM restrictor on the well pump, and using the float switch directly, without having a pressure tank and pressure switch, you maybe able to make the Symcom work. This way you can adjust the sensitivity to work at the amperage when the pump is restricted, and the pump will always be restricted. So the Symcom should work with the Dole valve/float switch combination.
A Symcom won’t work with a Cycle Stop Valve using the solenoid valve/pressure tank/pressure switch method. This is because the CSV would let the pump produce full flow and max amps when it first comes on, then it would reduce to low amperage when the CSV started working to restrict the pump to 3 GPM. The amperage range of the Symcom is not wide enough to let the pump work at high flow/high amperage AND low flow/low amperage.
The difference in the Cycle Sensor is that it WILL work at high flow/high amperage, and will still protect the pump if the amperage drops below the low flow/low amperage setting.