Siheyuan: Slapping Jia Zhangshi from the Start

The protagonist's parents are both alive, so he's not an orphan, and he has a happy family! No harem. Although there's a System, it plays a very minor role!

A 21st-century trainee police officer accidentally transmigrates to New China in 1951.

Faced with an entirely unfamiliar new era, he resolutely decides to join the army and fight the Americans.

Five years later, after leaving the army due to an injury, he returns to the courtyard compound and joins the security department at a steel mill! Thus begins his rise through the ranks as he takes on the scheming neighbors and protects his family!