I dunno, I wish my name was one where there was an obvious male version. It would be better if I had a more neutral name I guess. If I ever decide to change my name then I think I would ask my mum what she would have called me if \I'd been male.
I know what my mother would have named me had I been a boy, but it is my younger brother's name.
I wonder if your mother would have given you your younger brother's name if you had been born a boy.
Sophie means wisdom, so if you wanted a name that also meant wisdom that could be either a boy's or girl's name, you could choose Dara.
If you wanted a name that also started with So which was the name of someone noted for his wisdom, you could choose Solomon.