How to win with a “weak” Knight?

Of course, anything can happen. However, I have never seen a computer-controlled Castle with a level lower than 1-5 and a well on level 127 (and in some cases, even a green tower). Of course, it is also possible that the computer does not build Minotaurs or Hydras. In this case, all that remains is to tell yourself: "Well, I did everything I could, I captured the enemy Castle in time, but I was a little unlucky. But I gained additional experience, enjoyed the process of the game, and I will bring it to the end, despite the new obstacles. And next time, things will be different, and the computer won't let me down!".
It is quite possible to defeat the specified Barbarian army, but the question of how to take his Castle afterwards is not easy. In principle, with a strong knight, the defense of Gargoyles quickly exceeds 10, and Orcs in melee combat cannot offer any resistance, but there will probably be Goblins and even Ogres in the Castle:(((, so you have to rely on ballistics. Griffons will probably die in the battle with the main Barbarian forces, because someone will have to fill the ranks of archers. Medusas will survive, yes, but it is not very convenient to storm the Castle with them (I will probably describe this technique separately in a small section "On the question of storming a computer Castle with non-flying troops" as part of the work, either on tournament game techniques or simply on game techniques in the second Heroes game). Well, it's clear that you can't do without ballistics, but that's what makes the knight strong.