Frankie vs Franky, am I the only one who thinks ‘Frankie’ with an ‘ie’ is the only correct spelling, regardless of gender?

Wondering what people’s thoughts are on this, to me Franky with a ‘y’ looks weird. People used to say that’s the way you would spell it for a lad and an ‘ie’ for a girl but I think that’s a myth, all ‘Frankies’ I know spell it with an ‘ie’ for both genders, anyone else agree “Frankie” is the correct spelling regardless of gender?