YA Sci-fi book I read about 3 years ago where girl doesn't have any memory at the start but later learns that she's apart of some big organization

[Evelyn]

A girl wakes up in a mall and realizes that she doesnt remember anything. Later on in the book, she learns that theres a lot more of them in this group who all work for this organization. The organization will periodically erase their memories. Also, theres clones of this group and their entire purpose is to like defeat bad guys. I think theres also some kind of alternate reality part or alternate universe part to the book and theyre referred to as "Better Earth" where i think everything is made of gold.