I saw a very interesting video that explains why Russia initial plan failed and why they are not close to victory.
Unfortunately, it is in French. I still post it for those who understand it.
https://www.lemonde.fr/videos/video/...1_1669088.html
For the others, Russia lacks Sergeant or the equivalent to organize their troops in urban fights. Ukraine landscape is muddy at this time of year, forcing Russia to use roads and become easy prey for drones and air strikes.
They use soviet ammo which are mostly non guided, and this is why they could not suppress Ukrainian AA capabilities and air force.
They also lack in the logistic department, they lack trucks to bring supplies to the front line and those trucks have to use road as well, becoming targets.
Their army lacks morale as well, since it is not as professional as Western's one and most of them do not want to be there or do not even know why they are there.