Any ideas?

I wanted to check up on a manga I had read a while ago but can't remember the name of it, can someone try and help me? (description might not be too accurate)
So mc was born in a very poor noble family, so poor that he even had to help out in the fields. His sister got "sold off" in some sort of political marriage and mc wants to save her. Then mc magically gains powers, some sort of alchemy powers I think? Don't remember exactly how and starts emproving the quality of life for the people of his town. Mc has two older brothers and he has to prove to them that he is worthy of being the next person to be in charge (idk?). I also remember mc having a younger sister living segregated in like the castle's library? And somehow said sister eventually became like a baker? Anyways, hope someone can match up the description ty