If you look at history, especially ww2 this has been their doctrine. They fight very differently than the US does. In Iraq we bulldozed through but the Russians are just going around.
Just like the Germans struggled to handle it in ww2 the ukrainians are too. Conscripts first, find strong points and bypass with the trained armor units.
Germans did something similar with blitzkrieg.
The key of deep battle doctrine is similar to blitzkrieg: overwhelm a weak point, encircle, annihilate.
The difference with Russian deep battle doctrine is that blitzkrieg gathers one very strong armored push to outright overwhelm defenses while deep battle does reconnaissance in force with small units to find the weak points then surges reserves to the weak point.
Blitzkrieg requires actually physically encircling the enemy and fighting a battle of annihilation in the kessel, but as you see from the Russian moves here, they don't need to encircle fully or commit to a battle of annihilation. They've destroyed enemy reserves and supplies per deep battle doctrine, so they slowly close in while leaving a small corridor for the enemy to attempt a breakthrough (which is watched and if a breakthrough attempt is made, they'll be wiped by artillery and air power). Or the enemy can attack into a strong line and get wiped anyways. Or they'll just starve out and surrender.
We see a masterful application of deep battle in East Ukraine right now.
