Auto-translated
I'd like to add a bit to Qwerty's answer. The computer will never retreat if it can reach someone in the same round. Therefore, when, for example, an angel immediately kills a sacrificial unit (placed forward on the tactics screen), we attack it with all our might, and if we have a decent number of starting troops, we can eliminate 2 out of 3 angels in the first round. However, without tactics, your main stack will immediately come under attack from the angels in the first round, and in the second round, after the angels attack again, there will be no one left to fight. If you're taking a Dragon lair, you can also use a sacrificial unit in the second round, placing less valuable units in front to be targeted by the dragons, and they will definitely burn them. Below, in the screenshots, I've provided an example of Valeska, a level 4 hero without a spellbook, taking an Angel dwelling with attack/defense stats of 3/2, who has expert archery and basic tactics, as well as 28 archers with a screen of 2 horses, 1 griffin, and 20+1+1+1 spearmen. We place a single unit under the angel's attack, and then just shoot down the angels with archers, while the screen focuses on defense. In the case of angels without morale, the losses are 1 griffin and 9 spearmen. Well, if they have morale, you might even lose a horse. But you knew where you were going and that something like this could happen, but now you have an angel. It's much harder to break through the guard of this dwelling on a random map, but taking it is easier. If there's a similar situation, but without tactics, the morale that the angel receives in the first round will immediately lead to a loss, and even items won't help