He convinced Mayor Archhild to increase the interest rates in the bank in exchange for building a guild of mages in his city and depositing money there.

Oh, I'm glad someone used the bank. It's essentially a cheat and allows you to accumulate money passively if you find yourself in a difficult situation.

I often had to replay battles several times to finish without losses.

Probably, this is a manifestation of perfectionism. When I was testing, I didn't worry too much about losses, as there was generally enough money. As a result, I had about 50% of battles without losses, not 90% as those who posted their stats here did. The low creature growth rate should logically encourage you to periodically change the composition of your army. ;)

choosing the class of the starting hero

It was originally intended that you could choose a class, but the game has a very fragile balance. Necromancers are a cheat with raising undead, mages get all spells from their super ability, Barbarians and Dwarves are geared towards their own type of troops. The Dark Mage will conflict with the ability to buy enhanced Chaos spells. In short, this feature is not planned for now. Besides, you can choose any set of skills for the hero, playing as a warrior or a mage.