Why was Gaddafi beaten so badly by the opposition? Didn't the United Nations send ground troops?

At first, Gaddafi had the upper hand. However, NATO air strikes made Gaddafi's large equipment unusable, and taking it out was a living target of the plane. So Gaddafi's tanks, armored vehicles, planes and balls can't be used. Only the army, the author pickup truck, can use AK to fight the opposition. Rao, in the beginning, Gaddafi's people also used good organizational discipline training. However, NATO blocked the sea, with the opposition base camp in the east and the border with Tunisia in the west. A port to Tunisia occupied by the opposition appeared, and several opposition groups appeared in the south, blocking the throat of the capital and being besieged on all sides. The supply is small, and one bullet is knocked out. Not to mention that the opposition got a lot of materials, Britain, France and Italy also sent retired instructors of special forces to train new recruits for the opposition. At first, the opposition was all civilians at the front; Later, those who want to go to the front have to go through a month's training of special forces, and then they have to train for another month and a half before they can go to the front. All of a sudden, equipment, training and organization have been greatly improved. The opposition was originally numerous and had an advantage in number, and gradually became stronger than Gaddafi.