There should be no problem if sugar and MSG are put together! Many recipes and seasonings contain both sugar and MSG!

But you are talking about saccharin! I advise you not to add saccharin if you are eating it yourself. It is not good for your health. I can’t tell you the specific harm! But my family has not eaten saccharin for many years. I usually only put it in when making popcorn, and use it once in a while! Then there are some food processing plants that use it as a flavoring additive!

My personal suggestion is to use sugar! Rock sugar, white granulated sugar, soft white sugar, you can choose different types according to your needs.