Don't underestimate the Ukrainians. Their homemade drones were designed by native hobbyists. Saw one yesterday that could carry 6 mortars and drop them one at a time on Russian tanks. One drone took out three hidden tanks. The T-90 tanks were never designed to withstand a attack from above and that is where their thinnest armor is. Not only are the tanks being destroyed, but their crews inside are dying as well.