Saigon also has very unpredictable traffic, so if you get stressed easily, it makes sense to plan to aim to reach the airport 2.5-3 hours before your flight. My SO gets panicky, so I have made a habit of aiming to arrive at the airport an hour before I would if I was traveling alone. Last week, we had unusually light traffic on our way to SGN and zero lines at priority check-in/security, so were at the lounge 2.5 hours before our scheduled departure. Vietnamese lounges are nothing to write home about, but better than sitting in a Grab with a woman who's screaming, "we're not gonna make our flight." I suspect booking a transport/expediter package through your hotel would give you extra peace of mind, but IME they will also often err on the side of suggesting an early departure from the hotel.