ב"ה Shalom Thank you for those insights. So my follow-up question is: whats my hebrew name according to Halacha only? And is it OK to use David only? As a reminder, David was the only name given to me on the day of my Brit. I figure, this should be my halachic name. My parents added the second name Moshe a few days after the Brit, for no particular halachic reason. They just liked the name and there wasnt any known health issue. All my life, the only name thats been used is David only, including when called to Torah, except on my legal birth certificate which is David Moshe, but I understand that only has legal importance.

ב"ה As I explained in my previous answer on this issue , under certain circumstances, an additional name can be added after the Brit. Therefore, it would be incorrect to discard the second name given to you. Your birth certificate indeed has legal significance, but the fact that your two names were given there by your parents, to me it seems that is the name they meant to give you. Many people were given two names and they don't always use both names, however when called to the Torah and for other religious issues, the two names should be used. Therefore, it would be wrong, in my opinion, not consider your second name as part of your Halachic name., without further verification of more details. This should be done by speaking to your parents, Rabbis and friends of your parents at the time you were born and then speak to your local Rabbi. All the best