I’ve had exact same problem recently. The rear passenger side rim cracked on inside . 20 in rims . Never hit anything . First time I ever had a flat since I bought truck new.Just changed factory tires after 105000 km 3 days earlier at deskershop . Bought exact same Goodyear tires . 2018 Silverado. After 3 days I got low pressure alarm . Figured it was just a nail I picked up