Well, you can level up your hero, and even if the computer has an army 10 times larger, it's still not that hard to defeat him...

The problem is that there aren't many places to level up. There's only one guild of veterans and a circle with experience. That's it.

By the way, I'd like to offer you my new scenario.
Difficulty - Expert, Whirlwinds of War are required to complete it.
The only serious bug is that if the red player is defeated by someone other than you, the game freezes... but this is very unlikely, so I recommend saving periodically starting from the moment you can fight the red player.
In this scenario, I decided to create a kind of "correspondence" between artifacts and the environment. Here's an example to make it easier to understand: let's say you pick up an artifact, and the text says that you were digging in a pile of sand near the tavern in the Necropolis, but you are in a winter forest near a river (it's marked on the map). In general, read the story of the artifact you picked up and look at your location on the map.
The scenario can be completed; I've played it through 3 times myself, fixing bugs.