I don't understand the point of such large maps; it's just pointless, endless running around. To make it challenging, you should make it 1x7 and have fewer, less impressive barriers between locations. On any difficulty, the computer has much less chance against a player, especially if the player has had time to level up; even a significant advantage in troops doesn't help. There are too many artifacts on the map; I was selling them in whole batches, buying weekly growth in 4 cities just from selling artifacts from corpses. I collected all the sets available in the game.
For a month, I watched two very strong Necromancers "dance" in one place: one takes the building of the Scouts, and the other, on his turn, comes out of the Castle and takes it back, and then goes back into the Castle. Until the main character arrived and killed them both. I'm playing with a mod that gives the AI smarter behavior.

Added 6 minutes later

Hello, can you suggest a good map for playing locally with a friend? I'm looking for an interesting, large map, but the main thing is that it has more Artifact locations and Dragon Utopias.

There's a great map called KING, but it's designed for alliances, and it's a medium-sized map. The computer is very strong on it; you can find it here on the forum