With soprano and concert Ukes, there are limitations as regards keys and you need to go "up the neck" for many of the tunes to play them properly.

One suggestion if mainly playing melodies is to tune the G string an octave lower and this will give much more scope. It still sounds effective while strumming too. You will need to make sure that use the correct gauge, of course.

There are also lots of subtle techniques which can be adopted including the "campanella" but you require to retain a "high" G string for that.