Geez, if the resource expenditure is proportional to the army I'm going to go bankrupt, I'm very close to 3k guards.
by the way, I think we talked about this in the comment of the user named "rolo". i thought of a new solution to keep the number of soldiers in balance. the more soldiers you have, the more food you will spend. therefore, you will need to increase the number of soldiers in a balanced way. i will relieve you a little more in terms of resources with the new regions to be opened. (like looking for food in the forest we cleared)