Nice plan... for China, the only country that can mass-manufacture high quality cost-effective drones. Shoot down an American drone, US checks the bill --> "OK yeah that cost as much as a Raptor."
Also, the plan aims to use drones to buy time for the US to respond, making an initial direct invasion costly and difficult. But that's not how China would approach it because without substantially pounding ROC's defenses, the invasion would not begin yet anyway so China would actually use that time to clear the US drones as well. It would use up more Chinese ammo but it wouldn't even necessarily buy the US more time.