Aside from all the well-worn issues raised in this article- below, the elephant in the room is FOOD. Sure, that falls under "supplies" so there is that. Nevertheless it needs its own emphasis. If some food does not start coming into ALL of those occupied areas in the east, there is not going to be any people to either kill or be killed before long. As in one week or less. The Russian soldiers have been hungry since before they arrived. The plan was to travel light and fast and take Kyiev in three days or less and resupply from the airport. That convoy did not have even enough food to feed the convoy. Things got better a little bit when they were able to loot citizen's homes but now no one has any food- and where that is not true, give it a few days and it will be.
Yes, the Ruskies have expanded their territory in the east, especially, but what a mess. Putin obviously ramped up the pressure on them to advance and git er done and they have done that but it has pushed the men and the senior officers out front ahead of what they can hold without supplies. Some of those generals were a little more out front than they wanted.
Food. Napoleon said that an army marches on its stomach. Not a lesson the Ruskies have learned that well. They are able to whiz some supersonic missile into Ukraine that cost enough to feed an army for months-years or more, but can't provide a soldier with a box of crackers and a jar of Jiffy peanut butter. CMON MAN!!!
“The odds are stacked heavily in the Russians’ favor. This is their war to lose. The reason they are not achieving their objective is largely about their own incompetence, their lack of coordination,” he said.
“What this really comes down to is whether the Russians are going to get their act together.”
https://www.washingtonpost.com/world/2022/03/20/russia-ukraine-military-offensive/