That is very correct, its a misconception that the Soviet Army in Afghanistan was defeated. In the end, they got tired, their economy was worsening, so they packed up and left.
The Soviets never lost a battle on a battalion level. Most of the Afghan Insurgent Activities revolved around harassing Soviet check posts or supply lines. At no point were the Afghan Mujahideen ever in a position to capture a Soviet Base or a City occupied by the Soviets. Part of the problem was also that the Soviets were not well versed in Asymmetric Warfare, although they learned and adapted with time but initially they never not. You can look at these pictures as a proof. Most of the weapon systems that are present are heavy duty conventional warfare machines that are designed to obliterate conventional foes. Put this exact Army against any conventional force and it will decimated it.
Another thing, the invasion in Afghanistan stunned the Western Armies and especially the Chinese Army of how far the Soviet Army had come compared to its foes. The Soviet Engineering Core built roads, i repeat they built roads in a matter of days for its Armoured Columns to Advance. China had retreated 100 miles within its Mainland hoping that the natural terrain would hinder Soviet Armoured Columns. The invasion in Afghanistan proved that for the Soviet Engineers, 100km might as be 10km. NATO realized that the bridges they were going to blow or other terrain traps they had set for the Soviets were simply no match to the Soviet Engineers.
Imran Khan vs Pakistan: Protest of Treachery - Casualty Report