Oh
Greta for sure.
Gretel is too associated with the fairytale and
Gretchen is just very unappealing and almost harsh. very unapproachable too.
Greta on the other hand is more simple and warm. It's also just an all around beautiful name, at least in my opinion. This is the name that I used for the main character in a trilogy novel that I wrote, and also a name I also wouldn't mind using in real life. 😊