The need to backsweeten is typical of fruit wines, so I'm not surprised at your situation.I felt that the berry flavor wasn’t there until I backsweetened. On my first attempt I did it with 6 cups of sugar. It was cloyingly sweet, especially after a couple of weeks, so I made another batch and mixed the sweetened one with the unsweetened one. That one was about right, which is 1/2 cup per gallon. I’m making another now and I may use invert sugar so I don’t have to worry about it getting sweeter over time.