Not everyone wants an SUV or crossover. Buyers who enjoy sedans have a new one to check out. The 2021 K5 replaces the Optima in the US. Rakish good looks, loads of tech and value pricing make it a winner. Drives well too. How does it stack up against Accord, Altima, Camry, Malibu and sister Sonata? Tom Voelk checks out a loaded top trim EX model and takes a peek at a GT-Line edition.