Objective information can only appear after a series of tests.
For example:
1. One-on-one duel
2. Horde vs. horde (weekly growth)
3. The same battles with the Bless and Haste spells
4. Market – city vs. city (weekly growth)
and so on.

The most important things are quantity, cost, and special abilities.

In my opinion, the following table is the best:
1. Halberdier and Centaur, but Sprites are just awesome – a large projectile that will die itself, but can take a serious enemy with it.
2. Wolves and Harpies
3. There are many good ones here: Orcs, Dragonflies, Ice Golems, and Cerberi, in short, I don't know.
4. Vampires and Swordsmen
5. Here, I'm most afraid of Pit Lords – they deal massive damage, if they manage to reach you, of course; the most annoying are Eagles, and the most harmful are Gorgons.
6. Definitely Death Knight!!! These are truly top-tier creatures.
7. Behemoths.

As for the castles, the situation is as follows:
If the market is more like Might, then the Barbarian castle is the best.
If the market is more like Magic, then the Elemental castle is the best.
If the market is more like Might & Magic, then the Dungeon castle is the best.

In general, 3 heroes are very well balanced, except for the Swamp castle. Not only are the creatures not very good, but they are also in a swamp.

P.S. Thanks to everyone who read this. This is just my personal opinion, which I simply wanted to share.