Do I need to apply for visa to leave airport and come back before the flight?

Hello, if you want to leave the airport, you need to apply for a temporary stay permit at the airport and you should go back before the flight.
As for your luggage, you can contact with the airline and consult whether your luggage is delivered to the destination. If yes, you don’t need to worry about it.
If not, you can collect it and then store it at the left luggage office inside the airport. When you go back, you just need to collect it and check in again.