MC is extremely innocent and good-natured, but by the end you will get a choice.
I see your point, what does not convince me is the fact that shortly after the dead of the father the mc is suspicious of zeno and edwyr and it looked like he had a trail of clue that he was following, like the secret meeting with the other elders, the trade with the legue and finally the potions. This crate of potions is part of the smuggling with the legue and zeno told the mc and his sister that there was only food.
It's important to remember that after they saw the food in the crate that zeno let them open the sister of mc said "let's give zeno a chance" and then the mc and the sister help with the box. Why after discovering the potion the mc doesn't share the information with the sister or anybody else? Until the day before he was untrusting.
Until this point i was fine with the plot, it was very good and i was thinking: this is good, what's next?
And then the mc became a puppet of zeno, showing only a facade resistance and stoped thinking.