New Hamster Owner. Recommendations?

[BaoziDwarf]

Hello. I live in the U.S. and I have just recently adopted a hamster. She is a species of Russian dwarf (although whether she is a winter white, Campbell's, or a hybrid, I have no idea) and is probably no more than a couple months old. I did in fact adopt her from a local pet store. I'm probably going to lose a lot of points for that, as that was the first flaw in my research. I did some, but I will admit that at this point I don't think I did half as much research on hamsters as I did on leopard geckos when I adopted one of those, and I'm starting to think my hamster's home is unsatisfactory.

My main concern is the size of the cage. I bought the cage about 4 days before I got the hamster. I got the All Living Things "hamster starter kit", thinking that getting it all at once was a bad idea. The cage is 17.5 in x 13.25 in (44.4 cm x 33.6 cm) and it is a three level cage so it is 18 inches in height (45.7 cm). I have currently taken the second and third levels out of the cage because the plastic ramps are not connecting properly, and that was the first indication to me that the cage may be more than a little bit small.

The next concern of mine is the substrate. This came with the cage (as well as everything else that is going to be listed) and it is labeled as "fragrance free paper pet bedding". It says it is just made of "reclaimed pulp fiber" and claims to be "dust-free" but there is quite a bit of dust. It's also dark grey in colour which makes spot cleaning next to impossible for me, so any suggestions on this would be fantastic.

The food that came with the cage is also a concern because it contains lots of dried fruits, and I know that Campbell's and hybrids are prone to diabetes, and as I don't know what species of hamster this is outside of "Russian", I don't want to take any risks.

Also if you have any recommendations for toys or hideaways, because my hamster doesn't have a hideaway and she only has a wood block to chew on, so I figured some more stimulation may be in order.

Any suggestions/recommendations/scolding would be highly appreciated! Thank you!