Discussion about Dungeon (Dark Elves).

No, you probably haven't tested this option, have you? If we think about it, what is the main disadvantage of the Wizard faction? After all, every faction has its weaknesses. For Wizards, it's defense. It's completely absent, both as a skill and as a parameter. But if you manage to acquire it, and instead of magic artifacts, you equip artifacts that boost defense, and also cast mass Stone Skin... how will the Wizard troops then be worse than the Elf or Human troops? Even better – the vast majority of them have more hit points among all similar levels. After that, Humans deal much less damage, and Elves or Dwarves also have relatively low attack.

Not quite.
I turned to a power-based build somewhere around 2006, when I encountered a pretty good player using the Academic faction with Counterspell.
But I still always max out summoning magic.

It looks approximately like this:

Expert Attack - Battle Fury + Retribution
Expert Leadership - Rally Troops + Aura of Swiftness
Expert Luck
Expert Education
Advanced Summoning Magic up to Elemental Equilibrium
Initial Invincible - Dark Ritual.

Hero: Sorgan or Kifrah

Total: level 20-21, i.e., 4-5 weeks.

If there's time left, I max out Elemental Vision.

And against Dwarves, a purely magic-based build usually doesn't work.

Here, instead of Education, I take Wizardry, and sometimes instead of Summoning, I take Chaos.

When I took defense instead of magic, they tore me apart.

P.S. You can try taking defense instead of education or wizardry, but, in my opinion, it's less effective