The same thing happened in the original game; here, you can only hope for the opponent's fairness. This issue cannot be fixed because the probability of each artifact appearing and the strength of its guard are set individually (which is what makes IRMG good), so a specific artifact is placed on the map...
I was rereading the dialogues on this topic. I think this question is not trivial...
Lеха, maybe there's a way to make the artifacts appear randomly? Is it really that important to place a specific artifact? I think both the artifacts and the guards should be chosen randomly each time a new game is created.
It seems that castles and secondary objectives, and everything else possible, should be randomized as much as possible.