The Eldest Sister-In-Law Wants to Get Married for the Second Time, and She Criticizes the Powerful Minister's Brother-In-Law Like Crazy

A Clever Ancient Novel Begging the Male Protagonist to Be a Powerful Minister

It doesn't matter if the male protagonist is a prime minister or a eunuch. It doesn't matter if he has a love interest. The plot logic of the Machiavellian plot is normal and he has an IQ.