Guys, thank you so much for this topic, because neutral creatures, especially ranged ones, are my weakness. In principle, when playing as Ilfina, I confidently use a unicorn against level 1 ranged units and support it with a tent, and in general, against neutral ranged units, I run to the middle of the field and then directly towards them. When druids appear, I attack the neutral units with lightning, while upgraded fairies attack them with a swarm of wasps; if they are not machines or undead, I respond to ranged attacks with ranged attacks. But in the first week, I generally avoid attacking anyone above level 2... Maybe it's wrong, but it's for safety's sake. Otherwise... in campaigns, neutral units are a headache for me at the beginning. Closer to the end of the campaign, they are just easy to defeat (although in the fourth game, in "The Gathering Storm," my heroes were already running around alone from the second mission), but otherwise, it's a real challenge. For the Sylvan faction, Ossir and Diraell are good at clearing out neutral units, in my opinion - again, the strategy is to rely on ranged attacks.
I wrote this nonsense so as not to go off-topic.