Have you played Heroes 2? There's a scenario called "Pyramid" in it, and it's difficult.

In the second game, besides the Pyramid, there's also an interesting map called Pandemonium. I watched how its walkthrough drove three very good players crazy for half a day; I watched from the side and genuinely enjoyed it.

Added after 3 hours 10 minutes
I'm trying to defeat Xiedu and have encountered an interesting feature. Either it's a bug in the game or a bug in the map. In short, Sir Mullich doesn't gain skills when leveling up, starting from a certain level. At the same time, there are 3 empty slots. What the heck is going on?