Silly computer, can we get a fix?

I think that if you stop controlling hundreds of zombies with a single fake hero, teach the AI to use dispel during battles, utilize defensive abilities, avoid unnecessary risks, and manage resource stacks efficiently, then yes, the AI will become a bit more challenging, especially if it can "deal more damage."

It's unlikely that this will significantly help the AI player (if it continues to play with only 1-2 heroes without using hero combinations), but it will make fighting neutral creatures much more difficult (as it used to be).

And I overlooked the most important thing: the development strategy. The AI plays very poorly in this regard, building some nonsense and then heading to the Capitol (thereby wasting a lot of precious time). In other words, building cavalry in the city/castle on the first day is almost an impossible task for it. For humans, it's the standard approach. And if it's Jebus, then it's angels, no matter what.

Doomsday
The main thing is, if you start, finish it. At least create a patch for the battles.
I sincerely wish you success!

(Dirty, could you move the topic to the Heroes of Might and Magic III online section? Only 3.5 people will read it here, and you know that yourself)