Aw I know - it's great things have improved so much in recent years in hamster care! It's the last 10 years it's really come on I think, but mostly in the last 5 years. Many of us started out with a cage too small and upgraded

It kind of seems obvious now that they need more space.
As for food. Vita Garden Hamster and Gerbil used to be recommended as ok, although having just looked at the ingredients and guaranteed analysis I'm wondering if it's changed! It has hay high up in the ingredients list (not needed for hamsters. The protein would need supplementing as it's only 15% but that's the same for quite a few mixes. There are no other commercial mixes really with a good variety of ingredients so people tend to get mixes from Etsy or Getzoo! They can work out expensive. I'm thinking
@Hamster Haven may have more info than me about where to get the food as she is in the US

There are some "home made"mixes that are popular and have a wide variety of ingredients - some are better than others. I'm not keen if they rely on lentils a lot for protein. Partly because hamsters don't digest lentils very well and also they may not even eat them.
Protein needs to be about 18 to 20% but if a mix has less than that, you can supplement the protein with fresh food

Eg chopped hard boiled egg, nuts, and people get freeze dried chicken bites or shrimps as well. The ideal thing is a mix that contains everything or only needs a little bit of protein supplement.
Harry and Hazel Hamster are a fairly basic mix for Syrian Hamsters as well. Not the best variety but they aren't bad and are sugar free and contain all the protein needed. The pieces in that are a bit big for a dwarf hamster though.