2000 Nissan Sentra OBD Error Codes P0430 and P0217 - Check Engine Light On, Overheating, Driving Hesitation

I own a 2000 Nissan Sentra with a 4-cylinder engine, 1.8L, automatic transmission. The vehicle has been showing OBD-II diagnostic codes P0430 and P0217 for the past 4 to 5 months. The check engine light has remained on continuously. This afternoon, the temperature gauge spiked to 'high' levels, but returned to normal after adding half a gallon of 50/50 coolant mixture. I also noticed driving hesitation this Friday morning at 70 mph—specifically during acceleration and when merging onto the freeway, where the vehicle responds slowly and takes time to pick up speed. A smog inspection is scheduled next month, and I need help diagnosing these issues before then. The car is located in California, which has strict emissions standards. Any insights into what could be causing P0430 (catalyst system efficiency below threshold) and P021-7 (engine coolant temperature sensor circuit malfunction)?