nah, Leo works fine as a full name. it doesn't need to be a nickname for a longer name. 💙
Love it on its own
I don’t personally love such a short name as the full thing. I’d do Leon or Leonard if it was me but if you only like Leo he definitely won’t be the only one
leo as a stand alone name is completely normal! don’t need a longer name for it if you like it on its own ☺️