Thank you for the feedback!

Basically, I started with an overpowered Necromancer with 200%...

Naturally, like any large and lengthy map, this one also suffers from all the typical balance issues inherent in SoD and is probably more suitable for WT or for tournament rules using XL templates.

But I am against map creators strictly banning Necromancy, the Red Sphere, marine artifacts, certain heroes, etc., in the map parameters. This is still a matter of the game version and specific tournament rules and agreements: some people want to and play SoD according to well-thought-out rules, while others want to and play WT; it's a matter of taste.

I will say right away that the map is not suitable for rules that allow Necromancy to be upgraded as the last skill. You will be safe for a long time and get a level 20 hero when there are still many neutral creatures on the map. Honestly, I don't know how to balance Necromancy here without completely removing it.

the map is very long, towards the end, due to the labyrinths and teleports, it becomes tedious

Yes, I agree. If the goal is to capture all the castles, it turns into a nightmare. Moreover, the computer player is often quite strong, and splitting the army becomes dangerous.
I would like the victory to be awarded by capturing the opponent's starting castle, either red or blue, but, unfortunately, this is not possible in the SoD map editor.

- regarding blue, as I understand it, it is designed for the blue player to also be a human, but I set up an offline game and chose the computer, gave it Necromancer and Conflux, tried all the castle options, but it still cannot develop to the level of "green" and "brown"...

Yes, the surface players should be controlled by humans, not AI. You can probably play a hotseat game with your girlfriend and edit the map parameters, allowing her to play as brown or green. :D It is really easier to develop there than on the surface.