Charlie has never shown any interest in any toys in his cage! Unless they are food related or cosy. So putting bedding in his sputnik and a tube leading to it got him napping in his sputnik regularly. The Antos toothbrush chews are the only ones he showed any real interest in and got excited about. Although he would spend a fair bit of time chewing the rosewood naturals dandelion sticks. He ignored them at first but after a couple of days (with no sweeter option) he started demolishing them.
Out of cage is a different matter - he will spend half an hour chewing and ripping cardboard and hay off the inside of these
https://www.amazon.co.uk/Rosewood-Na...ottage+hamster
In the cage he just used it as a step to climb on and occasionally nibbled the top.
He does love this hyacinth tube though and uses it all the time - he likes going in and out of the holes and has chewed it in the past. It's nice and soft and no scratchy or sharp bits. The small size is also big enough for a large syrian
https://www.amazon.co.uk/Rosewood-Bo...yacinth+tunnel
There are other sellers on Amazon if you don't want an add-on item and viovet sell it too.
They can have a lot of fun with substrate too - the deeper the better - then they can pile it into mounds or dig under it. Sorry if you know that already
And scatter feeding gets Charlie quite excited.