The cage is perfectly fine in terms of sizing, although I do recommend getting a clear bin cage because it is better for the hamster to know when it is day or night. I do recommend getting a bigger wheel (minimum is 8 inches for dwarfs and 11 inches for Syrians) and also try to reduce the use of plastic items and add more natural items like wood bridges more chew toys. Other than that I say your cage is
perfect!
