Stronghold vs. Academy

No, it's too risky to upgrade all the suppressors at once, and even if you make a mistake with just one, it will be terrible. Upgrading defense is not necessary at all, only if there are no other options left. Otherwise, you need to organize a swift attack, with a tactic and a speed aura in the lead, and if you're lucky, with boots that give +1 to speed. Magical races don't withstand this kind of onslaught well, because Orcs themselves deal decent damage, and here there is also a huge advantage in attack. If everything goes right, the mage might only be able to cast a spell 3 times. However, if the mage gets ahead in development and the hero is more developed, these advantages may become insignificant. So, you shouldn't delay with the start. I would also upgrade logistics. You can also upgrade luck; choose Goblin Shamans, as their ability and the creature itself can at least disrupt magic once. And with soldier's luck, Orcish Warriors are more likely to make 2 attacks, which also helps. And if you're afraid that the mage will use Chaos, then magic resistance and barbarian luck will reduce the damage.