Both surnames and first names are just symbols or titles, and there is no distinction between good and bad. If you say that the surname Dong is not good-sounding, does that mean that the surname Gou is good-sounding? If you look up hundreds of surnames, you will find that your surname is stronger than many other surnames, so don't have any ideological baggage. Do you want to change your surname? No way.
You can choose a name based on your own preferences, ambitions, etc., or you can choose it based on homophones. For example, Dong Shichang is a homophone for chairman; Kechang is a homophone for section chief, just to give some examples. Reminder, hope it helps you.