Thailand or Vietnam?

Hi everyone! My partner and I are trying to figure out where we would like to honeymoon, and two options are Thailand or Vietnam. I’ve never been to the Asian continent and think it would be a great first adventure! We would be flying out of IAD or BWI and are thinking mid to late next year. Our ideal honeymoon has excellent food, beautiful beaches, and some added history/ cultural elements to explore. While I am not looking for luxury travel, staying in some very comfortable hotels with excellent service is a massive bonus. I’m torn because both countries seem so beautiful, so I would love to consider this sub's opinions and points when making our decision!! TIA!!!