Discussion of the Mirror Jebus rules.

You could edit the template so that dungeons are generated in the treasure as well, just like now, with the same guards, but the hero level would be 1, not 10-20-30, or whatever it is now.
In the treasure settings, you can set dungeons with an arbitrary hero level, arbitrary value, frequency, and maximum quantity.

Even if this is possible, the question is what value should these objects have? It doesn't seem right to attack dungeon guards with a level 30 hero and get a level 1 hero in return. Of course, it's not very pleasant when one player has a level 30 hero with top-tier upgrades at the entrance to the treasure, while the other has a weak one. But completely removing dungeons is not the solution.