The solutions already exist and have been proven on the battlefield. Peacetime military forces are just slow to adapt, as there are no real incentives to adapt quickly.

Drones such as the Shahed are little more than cheap mediocre cruise missiles. Because they are cheap, the enemy can launch them in large numbers. You counter them by detecting them early and then using plenty of cheap mediocre anti-aircraft weapons. Mostly guns and interceptor drones (=cheap mediocre anti-aircraft missiles).