Tactics for the Swamp (Fortress).

if the enemy closes in first - shield.
because taking only 10% damage is imba;)

Expert Shield reduces damage by 30 %

And a small imho about the swamp. (since over the years I've started to understand it a bit)
In Heroes III there are, I would say, "unfair aspects of army recruitment"
-necromancy
-demonology
-angels from cans
-geese from trees

meaning these aren't bought but obtained in battles.
The swamp has an advantage over others in using the 4th aspect. This is the ability to grade geese + their quantity is higher. That's one.

Second. The swamp, like no other, can easily take any tree and any tree guard on 1-2-1. Meaning the game scheme is simplified.

Build up max on the 1st [week] and find trees. The main thing is that they exist; taking them is no longer a problem. And so by the beginning of the second, we already have 2-3 hydras and 20 geese.

We go to treasury and take almost everything needed. If there are more trees there, the Dragon Utopia falls on the 2nd week, thanks to a powerful stack of monarch wyverns.

Accelerated scouts on flies help stretch chains much further.

In defense of lizards :)
Everyone considers them weak for a simple banal reason - because they are used without shooting and mostly ungraded. :) that's the whole secret.

Try playing as Vistan with graded lizards on 1-1-1 and I think many will change their opinion. (in TE, for example, he is actually started on maps more often than Tazara, because three stacks of lizards are guaranteed and that is great breakthrough power)