If you're talking about the "rebellion" map, I played it in hero mode and had no problems.

The orange elf that regularly appears from the southeastern end of the map is very easy to stop with city forces – that is, as soon as possible, build a Citadel in the city (you can't build a Castle according to the scenario), and it's best to leave all the warriors that appear in the city to guard it (although I did take all the elf archers). Until you reach the crusaders, no one will overwhelm you, and that's already at the end of the first month.

To the author, thank you for the instructions; unfortunately, I didn't think to check the campaigns and played the maps in scenarios, so I had to sweat a bit on the first city in Misty Moor – I took it with a level 3 hero with what you have at the beginning of the game – it's something, but I still took it, I can even send you a save. And after that, everything went smoothly.
I haven't played Peak of Stars and Stinking Swamps yet, and I probably won't be able to complete them with a level 1 hero.