The opponent restarted and eventually surrendered.
Considering the recent games where the lack of Earth magic skills significantly impacted the outcome, I decided to find an Earth magic skill as quickly as possible. As a result, on each generation on day 111, I got a hero with Earth magic: Grindan, Labeta, and finally, Deemer with Earth expertise and logistics (from the dungeon after about 15 ultimate dendroids).
Thank you for the game.