Hi. Yes unfortunately the Zoozone 2 has 2cm bar spacing which is too large for hamsters. You can get 1cm square mesh cut to the size you want at a diy store. You need to mesh the inside of the lid, because if you mesh the outside they can get through the bars and get trapped under the mesh. But also need to check there are no sharp edges on the mesh inside, either by clipping any protruding bits close with wire cutters, or, what some people do is fold the edges of the mesh under so there is no sharp edge - this can hurt your fingers so best to wear gloves when doing it! Probably easier to get a piece cut slightly bigger than you need and fold the edges under - then you use plastic cable ties to securely attach the mesh to the inside of the lid (especially round the edges). It's not as onerous as it sounds.
Sounds like you need to do it today before she wakes up! They can even scale up the side of a hamster wheel to get to the top so it does need doing and having lower substrate or lower items won't help.
Meanwhile if you can find something to put over top that covers the gaps but still lets air in it will help prevent her escaping - eg some wire cooking grids or something?
Here are some descriptions of meshing zoozone lids to give you an idea! This one uses duct tape at the edges. I would have thought that could be chewed but you could keep an eye on it and if it's accessible for chewing or starts getting chewed it would need re-meshing differently!
Meshing Zoozone 1
Here's another tutorial - also uses duct tape so I guess it's ok!
Zoozone ideas and adaptations
Another one here - no masking tape - it looks like you can do it without masking tape as long as there are no sharp edges inside the cage - but I reckon any cut edges would need filing to make sure they weren't sharp. On this one, the corners of the mesh protrude on the outside so no sharp edge inside, but might be sharp for the owner!
Confessions of a Hamsterholic: Zoozone 1 Review