Hello and welcome to the forum

Hamsters aren't great climbers, as you have noticed

It is better if they don't fall so far. Also the bar biting, which is very common, has the potential to damage their teeth. Both issues are very common problems when getting a new hamster, and both can be solved with tweaks to their cage set up. Ideally, once Muffin is an adult hamster, she should have at least 200cm by 50cm floor space to run over. The depth and kind of bedding is also important. Alot of pet shops sell new owners wood shavings as bedding, but paper bedding is much healthier and easier to maintain. It is designed for burrowing animals and ideal for hamsters. Muffin should have a depth of bedding at least ten inches and as much as twelve inches is perfect. Of course it might need to be lower in places to accommodate her wheel, which should be 12" in circumference for an adult Syrian hamster.
The deeper bedding will also reduce the height of the roof and help to prevent her from falling so far.
Putting cardboard against the bars will give her something to chew that won't damage her teeth and should also help to prevent her from climbing

A nice multi chamber house on stilts is the ideal bed chamber for hamsters. Or a shoe box with the base cut out and the lid used as a roof. This sort of house allows you to lift the lid