2) Are you speaking as a Cerberus? Actually, you are partially right, but the whole beauty of it is that between quantity and quality—I choose quantity. It's no longer important who is stronger, a Cerberus or a Demon; what matters is that you bet on Demons. By the way, it is very convenient to simply develop a tactic for one type of unit.
PS: In the end, with such a tactic, my army contains Devils, Efreets (two powerful flying units. Fortress is not a problem), and a huge number of Demons, who have to be split into several figures.
And all my mathematical calculations are infinitely rough and inaccurate, although they reflect the essence of things.