24 templates.

What about the idea that after a defeat, you would only retain the land you initially chose... Meaning, if you win 3 times, you already have 4 pieces of land, but if you lose, the winner takes 3 of your pieces...?
Is the idea clear...?

Another option is to gradually increase the stakes over time.

For example, for the first 2 turns, the battle is for only one piece of land belonging to the defender, and the attacker doesn't risk any of their land.

Then, for the next 2 turns, each battle is for 2 pieces of land belonging to the defender, but the attacker risks one piece.

And so on.