Tactics for the Swamp (Fortress).

By the way, taking a Dragon Utopia in week 2 is a utopia :-)
Even if it's the easiest one. (Well, in theory, of course, everything is possible, but in practice it's hardly feasible)
If you get lucky in week 4, you can sweat a bit - earlier is unlikely.

Speaking of L, XL random on SoD 3.2, by week 4 Dragon Utopias are easily taken by any castle. In week 3, things are worse, but it's still realistic, though Fortress stands out positively and has few problems. In week 2, a Dragon Utopia with 3-4 Azure Dragons is easily taken by a Necromancer, but only by them, who on average have around 700 skeletons by day 12-13. Fortress can only manage with substantial luck.

And only on L and XL maps. There, Fortress absolutely DOES NOT RULE, and Necros are also, by the way, not exactly the strongest (if, of course, they haven't found the Cloak of the Undead King).

When playing against equal opponents, a Necro versus another castle will win in 9 cases out of 10, at the very least.

Besides, colored dragons aren't really that scary for Fortress - Manticores feel an unnatural attraction to them, almost indecently so...
In my opinion, Fortress has a different problem - few high-speed units.

Exactly. Also, playing Fortress is difficult without experience; not seeing powerful shooters, many believe that serious losses are unavoidable and give up. But the Lizardmen are far from a useless unit.