I was browsing the internet and I found this https://www.youtube.com/watch?v=1WO0zSStdj8
Apparently, it's a squad of Russian Soldiers refusing to go back to the front line. The fat guy says they were NOT getting food or water (yeah I heard it), I am pretty sure he is right. So, what are the types of conditions you have to face to get water and food at soldiers? I mean, I can understand them not getting ammo and man power to get rid of the dead. Probably manufacturing problems and it's dangerous respectively. But yeah, what else? Why would they not get food and water?
You might want to read about tooth to tail ratio on Wikipedia
https://en.wikipedia.org/wiki/Tooth-to-tail_ratio
In a sense, war is mostly logistics. It doesn't matter how strong your unit is, how clever you tactics are, or brilliant your strategy is. None of those things matter if the unit is not where they need to be, with the supplies to be effective.
Most countries have limited ability to project military force outside their country because the logistics become so hard to support. Russian military relies heavily on rail transport, which doesn't extend into Ukraine anymore, and trucks what it can't rail…but the supply depots need to be hundreds of km behind the line because of long range precision missile strikes. With long supply chains supported to heavily stretched trucking, guys at the front won't get everything they want.