We have been living in Vietnam for almost 5 months and I have to agree that it's not a foodie paradise in the same way that Thailand is (for example). There are some things that a pretty delicious though. Huế is really the culinary destination in the country but you should be able to get some good stuff in HCMC. Try Bún chả Ha Noi (obviously from the North but we found a great one in HCMC) and try to find a "bang mi" 🤣 🤣 🤣 (bánh mì) that is mystery-meat free. Of course, the standard one is just as you said but you can find some damn good ones with actual grilled meat and fresh veggies. Bánh bao is another favorite of ours. Hope you enjoy your time here!