Mages – their development.

Read the topic. =) Based on what I read, I concluded that a mage needs to level up spellcasting, summoning magic, education, and magic of light/darkness/chaos, according to their preference? Another question about the new battle mages - they also deal damage to their own creatures. What's the point of them then? After all, archmages reduce mana costs by 1/4 just by being present? Also, I would like to know which creatures you upgrade to. I really enjoy playing as the Academy, but even my large army is easily defeated by the opponent on MEDIUM difficulty, especially at the beginning. I fight every day, and sometimes I don't even take a turn just for the sake of it; I try to plan several moves ahead. And still, they kill me. In addition, I tried setting up battles in duel mode: mage vs. random, and the result is always the same - defeated mages, regardless of whether I play or set up an autobattle, just to see. Conclusion - mages have some quirks that I don't know about. Please share them? =)