Walkthroughs for custom maps.

But first, you need to defeat 1500 Red Dragons.

And after opening the blue tent, the AI will come with Titans and Rust Monsters. If it's affected by blindness, the battle won't be that difficult, but killing 250-300 Titans will be challenging.

My tactic against the Minotaur was to take a Black Dragon and Harpies, use the sands to cover the entire area, and after he runs out of mana (he has almost 2k), resurrect the Harpies and kill him. But besides the explosion, he doesn't cast anything else.

Theodore somehow managed to open the Guardian without taking the Green Tent, but even though this helped me because he lost some troops, is that how it's supposed to be?

Also, another question, to save time, I didn't take the Water Orb. Is it even needed on this map? I just haven't encountered a place where it would be useful yet.

Yes, it's a pity that I didn't guess the secret. But I remember that at least part of the battles on such maps are won precisely due to the convenient terrain of the battlefield.
Why I don't like this: because it's no longer "Heroes of Might and Magic", but "Heroes of Might and Cunning/Dexterity". If I could cast spells in this battle (at least a force field or quicksand) or if the hero had troops with a petrification effect (basilisks/medusas) and I could immobilize the Cerberuses and thus block the passage for the rest, I would still fight. But as it is, the "secret" again turns out to be that the enemy units are acting stupidly, as we need them to.
And does this guy really need to be killed right now and with this hero and these troops? I moved the heroes away and waited 2 days, and I saw that a strong Brown hero is coming from the south, but the jerk ignores this enemy and goes straight north (to my heroes).
In "Wayfarer", at least, nothing like this happens: most likely, if you maneuver, you can pass very quickly and with small troops, but "traditional" methods of destroying enemies work quite well.