How to win with a “weak” Knight?

No matter how many times I play as the Knight, the strategy is always the same: capture something that's weakly defended. If it works, great; if not, we start over. Otherwise, all those long, fair battles led by a Knight hero with 10 Crusaders and 50 Rangers will end badly. He'll win 2-3 local battles and then lose everything. For most maps, I take the Beaver as my second hero, and he becomes the main one. Because Pesfindin is incredibly powerful almost everywhere, and no one has ever died from a lack of Leadership. Ballistics will help, but Wisdom isn't that important. Then, the Beaver levels up on 1500 experience chests and gazebos, we gather whatever army we can find, and by the beginning of the second week, we can already set off, especially if the goal is to defeat the Warlock. If we capture his Castle on the 13th-14th day, and use the money saved from not buying a bunch of living creatures, and the sulfur we collected somewhere, to build Green Dragons, then we don't need to worry about how many Crusaders our hero can defeat in one turn against the Warlock and his Lightning spells. Of course, this is an ideal scenario, but it has happened exactly twice. I somehow managed to take his Castle, barely surviving with about 5 Pikemen. Then, the Warlock arrives with 5 Hydras, 15 Griffins, and 30 Centaurs, but he can't defeat the Green Dragon because the Castle's defenses are strong, and the hero bought a spellbook in the enemy Castle. The hero's stats are something like 9-4-2-2. Of course, there are glitches in the AI where, on the 8th day, an empty or almost empty Castle is available, so you can just walk in and buy any army. But that doesn't always happen. In Seven Lakes, I managed to capture the Wizard's Castle on the 8th day, arriving from the island, and once there were even Giants there! But more often, there are 2 Mages and Golems, and no matter how many Medusas you buy along the way, even if there are 5 of them, and even with some Goblins joining, they can't defeat them. And sometimes, the Wizard doesn't even let you get close to the Medusa Hut. So, this setup leads to success 95% of the time.