If I was DD1 and decided I wanted to change my name as an older child or teenager, then I don't have the option of using my middle name.
If I was DD2 I would probably think there was a bit of lazy parenting here, that you couldn't be bothered to find me a name that was all my own.
I speak with some experience here, my first name is to honour my aunt, my middle name is to honour my mother, I am reasonably sure my dad had the deciding vote here. DB1 was given the same name as my dad and my cousin. DB2 was given the same name as my uncle. DB3 got lucky and got a name that is all his own, there is no confusion about which person is needed when his name is called. I hate my name, it's a perfectly lovely name but I hate having to share it with such a close family member. There was such confusion when my aunt lived with us for a number of years when I was little, to this day she will answer questions that I am pretty certain were addressed to me.
Please look harder, there are so many lovely names out there, you will find a special one for your daughter. So the name is sentimental to you, find another sentimental name.
If you want to be brave and tell us DD1's names, then I'm sure someone will be along soon to suggest a lovely match.