The map had no bottlenecks or hiding spots, but I managed to get some archers from the Pandora's Box. I decided to make the Valkyrie my main unit. In the end, on turn 122, with 2 Archmages and 100 archers (no Earth element), I defeated a Necropolis stronghold (dealing 1 stack of damage with each attack). But the time was very tight. And I stood as a Valkyrie in the center for 2 turns. The game ended. Thanks for the game.
So, due to the time pressure, I made a mistake and attacked with only vampires against bone dragons.
Well, they obviously didn't regenerate, and I lost 7 out of 30.
Then I thought that 23 vampires would be enough against giants.
There was a large stack of them, about 35.
If I had a full stack, I think I would have killed them.