Walkthrough for the "Tribes of the East" expansion.

I had 4500 centaurs and 180 cyclops.

How much game time did that take?! Personally, I didn't rush through it; I explored the entire map, visited all the upgrade locations, and even dug up the Tear of Ascha. Honestly, I think it could have been finished much faster, but I have a habit of maxing out everything in each scenario. Even so, by the end, I only had "about" 1100-1200 centaurs, roughly the same number of goblins (though trappers, I didn't think about shamans), and the rest in corresponding numbers (I don't remember exactly). However, Gotai had a maxed-out Special Ability.

I didn't immediately attack the walls; instead, I bombarded the enemy's troops with centaurs and goblin shamans (with the help of cyclops).

In my opinion, that's not the right tactic. Using cyclops for ranged attacks?! In my view, they should be thrown at the walls as soon as possible to break them down. Ideally, their speed should be increased with shaman spells. And if morale drops (which happens very often), they will quickly be behind the walls, and then the enemy will be in a very bad situation. And then the rest of your forces will arrive, and that's the end for the enemy...

PS. A small digression (read: off-topic). When I played through the Orc campaign, it seemed like they were completely overpowered with their Blood Fury ability. And many people here on the forum think so too. So, I was very surprised when, in the last mission of the last campaign (for Zehir), I was soundly defeated by demons while storming their castle. That's who is really overpowered: demons with their summoning and initiative. And yet, people say that demons are weak! When they are constantly moving (due to their initiative) and preventing you from building up Blood Fury, and at the same time, their numbers double, there's no question of them being weak. And goblin shamans don't help, because they can only disrupt magic once, while the enemy hero manages to take two turns before their next action. And Mass Slow and Mass Weakness on orcs is a death sentence.
In general, I replayed that battle five times, barely managed to win (I even thought about quitting the game before finishing it).
PSS. But there were no problems in battles for the dwarves and humans.
PSSS. Or maybe it's because Kujin was not leveled up enough? Although I also maxed her out everywhere. But still, playing as Gotai would probably be much easier.