What existentialism books should I read?

I'm recently I interested in existentialism and structuralism, and I've searched some information about them on the internet. While they're pretty easy to understand, they do not profound as much, so I decided to start reading some books about them. However, since I am not a professional English speaker, most books are hard for me to understand. Do you have any recommendations for those who have immatured English skills? My current English level is around B2.