Tactics for Dungeon.

Let's compare...
In terms of special buildings, the castles are roughly equal, as (Artifact Merchant, Library, Wall of Knowledge, Watchtower, Sculptor's Wings) = (Artifact Merchant, Academy of War, Summoning Portal, Mana Vortex, Mushroom Rings). Of course, it's a very rough comparison, but they are still equal. It is also worth noting that these are the only cities that have an Artifact Merchant.
Let's move on. I think it makes sense to compare only military buildings (by price).
Tower - 54300 (gold), 115 (ore + wood), 102 (other, including 60 - dragon stones).
Dungeon - 53900 (gold), 134 (ore + wood), 87 (other, including 54 - sulfur).

Conclusion: The Tower, although insignificantly, is more expensive.

Army (upgraded units):
1) Trogolodites (price of one unit - 65) vs. Goblins (40).
The advantage is with the Trogolodites.
2) Harpies (170) vs. Gargoyles (160).
Harpies are definitely stronger here.
3) Eyes (280) vs. Golems (200).
Despite the different tasks performed by these creatures, the Eyes look preferable.
4) Medusas (330) vs. Mages (450).
Mages. No comment.
5) Minotaurs (575) vs. Djinns (600).
Difficult to compare.
6) Manticores (1050) vs. Nagas (1600).
Nagas.
7) Dragons (4000 and 2 sulfur) vs. Titans (5000 and 2 dragon stones).
I think they are equal.

In the early stages of development, the units in the Tower are cheaper and weaker than in the Dungeon.
Later, the situation changes.

Conclusion: I still believe that Tower = Dungeon.