From what I understand from various sources, the primary causes of the fall were lack of artillery shells on the Ukrainian side, a heavy fog that rolled in for a few days that kept the drone from being effective, and lots and lots of very large glide bombs lobed from long range by Russian aircraft. Even with all of those things the losses were absolutely horrendous on the Russian side as you can see recounted from a Russian source here (you have to keep clicking through on the side to get to get all of it). A list of all the different Russian formations that played a roll can be found here.

The below video gives you the news and overview

This gives you background on the reasons for giving up….