[cypher]

I don’t keep Syrians so probably not the best person to give you advice but a few things, as for the food, they do have slightly different nutritional needs so the dwarf food isn’t ideal for a Syrian, if your ham likes it then it won’t do any harm, Rodipet do a Syrian food but I think most people do tend to stick with Harry Hamster for Syrians.
You may find that you will need to upgrade the cage as he grows, the Hamster Heaven is ok as a starter cage but a bit on the small side for Syrians, once you have the big wheel in there it doesn’t allow much room for burrowing in deep substrate so that may be something to think about.
Do you have a photo of your cage set up?
What kind of house do you have for him? Syrians do need a large house, shoebox size with no base on deep substrate.
The substrate mix should be fine although some hams have problems with carefresh & shavings, the kaytee clean & cosy is fine on it’s own really.
Have you tried whimzee dog chews, the toothbrush ones most hams love those more than other chews.
I would stick to natural treats, seeds like sunflower, pumpkin, hemp & flax, all in moderation, mealworms are fine but again not too many. If you ham enjoys them you can try putting millet sprays in the cage.