One of the things constantly brought up is how Putin is making all of his decisions since Covid in an information bubble where he is only being told everything is going fine by Yesmen. Shoigu is one of the worst doing this, just look at this clip of what he's telling Putin about the state of the war. This coupled with Putin's current Covid isolation induced illusions of restoring Russian Imperial grandeur, and you have leadership that won't be budging on peace any time soon.
https://twitter.com/user/status/1671823634552299520
https://twitter.com/user/status/1671824073482018817