It's strange, I might have set something up incorrectly in the editor. In any case, the map is considered completed, I'll go home and change the objective in the quest, and then I'll try it myself and update the map file if it works, although it's strange, I set it up so that you need to capture the artifacts, but okay, I'll fix it sooner or later, but I can only do it in the evening, if not today

Added 1 hour 43 minutes ago
I even specified "Obtain Artefact" in the quest.

As I understand it, using the standard quest editor, you need to create a separate quest for each artifact. Therefore, I implemented it using a script (I'm currently checking if Valeria has all three artifacts, but I can make it so that any hero can collect them). As a result, I made the following changes:
1) Fixed the quest for finding the artifacts
2) Removed these three artifacts from generation (so they can't be bought in the shop or found in Utopia)
3) Disabled the Astral Gates (so there's a reason to look for the keys)
4) Made it so that enemy heroes cannot take these artifacts