Can you explain the system in more detail? What level of the hierarchy does the player directly control, e.g. the unit, the squad, etc.
Usually people ask for less detail
There are 4 types of individual unit. Leaders, Heroes, Mages, and regular units.
You can control all of them as individuals. You can also assign regular units to leaders, mages, and heroes. You can control any level of the hierarchy directly from single units to hosts. You could even select a group of regular units not assigned to a leader and it would work like a regular RTS game.
However the game is designed to possess Sim, TBS, and RPG features and systems so if you spent all of your time microing your army you would be falling behind in research and economy and you wouldn't have time to decide what to do with RPG stuff like raising stats and having mages learn new magic and such.
The hierarchy works hand in hand with toggled and selected settings/commands and the unit automation to let the AI fight battles for you. You would normally micro only powerful mages and heros if you microed anything in a given battle.
So you could make a cohort with 5 squads of melee and 3 of archers and 2 of cavalry and one of mages and set the melee to hold a line, maybe a line 1-3 layers thick, tell each squad of archers to focus a single enemy mage or default to enemy archers if no mages are present. Then you set your cavalry to auto flank and charge enemy support, or even attack the melee line from the back and cause the enemy to route. Or w/e. And mages could be set to cast buffs or to cast attack spells. The units would do all this automatically.
But maybe you are looking around and deciding what you need to focus on at this moment and that cohort is doing badly in a fight, so much so that its more important to help it than to do anything else, and then you are perfectly capable of changing orders or controlling the mages individually or maybe microing one or more cavalry for better flanking.
The game is more like grand strategy than a traditional RTS. So the hierarchy and automation is so that your armies can handle themselves unless they are outnumbered and maybe even then, but if they get into trouble you can use your skills as a player to try and save them. The City Builder/Sim aspect has a similar level of automation. Theoretically if you are just not good at city building you can set up some simple automation and get by while focusing on fighting, but if you are not super good at tactics you can focus on min/maxing your economy and let the automated armies protect you.
And if you are good at both you can focus on whatever you need to at the moment.