Book Transmigration: I Use the System to Face-Slap My Wicked Mother-in-Law's Family

After transmigrating into a book, she takes the side of an abused daughter-in-law and trounces her evil mother-in-law and the rest of the family. Her golden finger is a System. There's a romantic pairing, no angst, and a domineering CEO from the 1970s who absolutely dotes on his wife. This is a hilarious, immensely satisfying period piece.