Current questions and answers regarding the map editor.

because I was planning to create my own hero with his own icon and other settings with that name (I wrote it now so that the scripts would work), essentially, does anyone have any more ideas? (it's a pity for the weeks of evenings wasted)

I don't think this error is fatal or unfixable. For starters, I can advise you to get rid of the Russianized editor: it is less stable than the English version.
Then you can try copying the map in parts to a new one. First, GroundTerrain.bin and UndergroundTerrain.bin. Then - objects (in groups, not all at once), regions, tasks, etc. Save each subsequent version, and as soon as the error reappears (if it even reappears), it will be clear what exactly caused it.