Hi, you said your hammy doesn't dig but I saw you are using sawdust, have you tried different substrates. I used sawdust when I first had Luna and she didn't burrow/dig around in it. I switched to maegazorb and she burrowed/dug around straight away.
Also I could't tell from the photos but is the top mesh, if so, could you hang some toys from it, I mean something like this
https://www.youtube.com/watch?v=4POWE_e-CGc&t=3s