I heard one analysis of this attack has to do with the ebb and flow of offensives/counter-offensives and also about Russia’s volunteer vs conscript troops.
Militaries can usually only support big offensive operations for so long before they need to go back on the defensive, build up reserves, and equipment again, while the other side goes on the offensive. And it goes back and forth like this, almost cyclical. Russia has recently been on the offensive for weeks/months now, but they’re coming close to reaching the end of this “offensive cycle”, they’re about to transition back to being on the defensive and waiting out Ukraine’s counter-offensive. So what this attack seems like it may have been designed to do is to keep Russia on the offensive, since taking territory inside of Russia is NOT something Russia will back down on. Ukraine taking their own territory back is whatever, but taking Russian territory? Putin can’t lose territory and will have to respond. All this basically keeps Russia on the offensive, which gives Ukraine a slight advantage as a defender while Russia throws more troops against them. The idea is to wear down and split Russia’s forces.
The other thing is the idea that Russia’s military is basically a two-tiered military, with Volunteer troops coming from the poorer, outer regions of Russia, they’re joining for money and it’s not as big of a deal when they die in droves in Ukraine, whatever. Conscripts, on the other hand, are drawn from the inner, more middle-class areas of Russia, but those aren’t the troops that typically go out to Ukraine. Those are the troops that most Russians in the more well-to-do regions know and they’re not typically put in the line of fire, they get the “safe” jobs defending Russian territory. So they’re probably not as battle-hardened, and if Russia has to start using Conscript troops in the fighting, it starts getting felt by the average Russian. War is no longer this far-off thing that doesn’t affect them, it’s their family members that start dying now and potentially pushes the Russian public more to start caring about the war.
Still early though, so maybe it doesn’t do much to push the needle, but it’ll be interesting to see how it all pans out.