Tactics for the Swamp (Fortress).

On a small map and before level 15, you won't be able to build up your hero—the game will be over.
And hydras on small and medium maps are just a toy, a waste of resources that you still have to scrape together (at 200%).
In a difficult battle between heroes with large forces, you can not only lose almost your entire army, but conversely—lose only 10 - 30% of the army (depending on luck).
Actually, the Complete Collection is just SoD, but with added campaigns and scenarios from the previous parts (RoE and AB). And troop experience and other crap go into WoG, which is not discussed here.

bolotnikthe spirit of gloom and the clocks that remove luck, whatever they are called, are needed by the necromancer since undead have no morale or luck.../QUOTE]
Everyone actually has luck, even necros.

well yes, I agree....
my apologies for the mistakes, I've figured it out.

it's just that I usually play large and very large maps, often custom ones, and there is obviously plenty of room to build up the hero, and more troops to collect, which is why the clashes become significant. I chose that hero level simply because around level 20 to 23, all secondary skills are maxed out. So it's conditional. On medium and small maps, you might not even make it to level 10 (everything ends faster, many monsters aren't upgraded and some can't even be built).
On small and medium maps, the game is faster, more dynamic...
Well, tactics and the choice of actions generally depend on the map, its density, size, and so on...
Building scheme:
1st week:
-lizards (if the gnoll dwelling is already built at the start, then day 1, usually if difficulty is not 200%)
-wyverns (if resources allow and difficulty is not 200%, then day 2-3)
-serpents (then definitely upgrade days 3,4-4,5; if resources are tight and there's no chance for wyverns, they are built on days 2 and 3)
It is desirable to have the resources to immediately buy the creatures from the built dwellings..
then a level 1 mages guild (it's better to find 500 gold for the book, as there will likely be cure or remove curse spells, which are useful when encountering an enemy hero.
After that, I usually don't build anything, I save money to hire creatures,
Then on 121 troops are bought, preferably hire some hero there as well, after which the troops are brought to Bron, who with such an army will already be able to break through to the enemy; well, the tactics there are actually simple: gnolls are meat, shooters provide support, the main strike is dragonflies and wyverns (mandatory wait at the start of the battle, then dragonflies remove the retaliation and weaken, and then wyverns deliver the main strike, [that's why I sometimes like to take the hero Korbak, a serpent specialist, to slightly improve their stats, as serpents are used to remove retaliation, apply weakness, remove beneficial spells, also it's worth separating a few dragonflies from the main stack into 1s]), basilisks for support, they can be used together with gnolls to pin the shooters in a corner. Of course, there can sometimes be gold problems on the Queen's side and buying everyone, but overall there are usually no such problems...
As a result, in the 2nd week on a small map, the breakthrough begins with the goal of attacking the opponent. Neutrals on standard small maps, and on random small maps, are usually not strong and should in principle be cleared easily by such an army. Therefore, by the middle or end of the second week, a meeting with the opponent is expected, and accordingly, with correct and reasonable further tactics—victory; the main thing for flyers is to use wait first, and then act.
On medium maps, everything is slightly extended and you already need several heroes for scouting, clearing, and then passing troops down the chain to the main hero...
Everything changes on large and very large maps, especially if there is a Dungeon and many castles; there, as a rule, all troops are built (upgraded), and heroes get all secondary skills maxed out. Due to the presence of other towns and mages guilds, there is a large choice of spells. There, the best tactic seems to me to use two strike stacks: basilisks and mighty gorgons; for removing retaliation, either gnolls or dragonflies with weakening are used, after which basilisks strike first, then gorgons strike; wyverns are used either for the pile-on (swarming one stack, or blocking shooters, or attacking and weakening some other stack), and hydras, due to their non-retaliating attack and attacking multiple units, are better sent to attack several stacks or a strong/strike enemy stack. Magic usually takes a secondary and auxiliary character (if ours are slowed, blinded, or something like that, we heal them); if the enemy used it to buff their own, depending on the circumstances (if there is no mass dispel, but it's best to have a water expert—mass cure, dispel, bless, plus enhancement of ice bolt and earth—mass slow, stone skin, shield); if it's strike magic, then for buffing your own or weakening enemy troops. Against neutrals, it's all simpler. Against the computer, everything usually goes fine in principle.
Against a human player, of course, everything becomes significantly more complicated.

But XL maps, especially with +U, and L as well, allow combining tactics and troops, spells, as it becomes possible for a hero to collect troops of different races. Moreover, when playing with the computer, it gets the chance to develop and accumulate strength, to evolve, so battles with it will be more interesting and more difficult.
Well, that's roughly how it is...