Silver is right knotty. The mix you are using is okay (I use the Burgess Supahamster but not the dwarf version, the one with the syrian pictured on the yellow bag) and I have a roborovski and a syrian. None of which are diabetic prone so I don`t have to worry about diabetes.
I did have a chinese female however and I fed her this same mix because it has more grains in it than the dwarf version, but I removed all the yellow corn/flaked maize, pea flakes and alfalfa as the alfalfa/grass pellets never got eaten. I`ve never had a hamster, mouse or a gerbil eat those!
So yes, I agree that looking at things like millet varieties like a canary mix, which usually has linseed and hemp seed already in it aswell as a mix of millet seeds and sometimes little bits of yellow egg biscuit, which you could also buy loose from a pet shop. Rat Rations sell this aswell, but Silver`s mixes have egg biscuit included.
You could also safely add plain porridge oats dry to their mix.