As a native Hungarian speaker, I would take this job with full confidence. I've been learning English since my childhood, used it, and also graduated from high school in such a language. I have experience with native speakers as I spent considerable time in England. I also consider it important to emphasize that I also used the language in different fields, especially in economics and management. Regarding the certificates, I have a C1 level exam.
I have a flexible schedule and good communication skills which can make it much easier for us to work together during the project. If necessary, I can stand well in a team (with subtasks).