I think the Alaska is better than the Mamble anyway
The Mamble does have bigger floor area, but is very tall and very hard to set up to avoid injury from falls, which ends up costing quite a bit more money in shelving too.
68cm isn't too bad but it sounds like your hamster does need more space. Also as alpa says they do need a 28cm diameter wheel.
That can be another reason for bar chewing - if the wheel is too small it can cause them back pain as they run with a bent back - and then they either stop using it, or get frustrated and want to be out more for exercise.
Bar chewing can sometimes be to try and get your attention (as it sounds like here!) and sometimes you have to work out if they are really trying to tell you something. For example if something is broken, like a ladder,and they can't access food or water on a shelf, they will frantically bar chew to try and tell you. Or if a wheel is jammed and not working. So it can be a kind of communication as well.
I'm sure your hammy will really like the Alaska cage. Some tips!
Fill the base with substrate to just under the edge of the base. The more you put in, the less you will use in the long run because you don't need to change it all so often and can spot clean mostly. So it ends up working out cheaper, but also allows more natural behavioiurs (they get busy digging, building mountains out of the substrate, burying hoards under the nest etc). But it also cushions any falls if they happen to monkey bar across the roof at night when you're asleep!
If you're getting the Alaska from Zooplus and you don't have a wheel big enough, then the 28cm Trixie wheel is cheap and will come postage free if ordered at the same time as the cage.
https://www.zooplus.co.uk/shop/small...r_cages/284288
https://www.zooplus.co.uk/shop/small..._wheels/174195
If you don't want pink then email them at the time of ordering and say - any colour but pink!
Also moving them over to a new cage needs to be done carefully so they settle in well. Otherwise they can have a complete funk at the change and get very stressed. Doing it cold turkey can cause that.
It's a good idea to set up the new cage with substrate and a couple of tunnels or toys and maybe one toy from the old cage, and let the hamster just have a play time in it the day before moving. They either explore and enjoy it and look happy, or freak out and want to come out again. If they freak out, put them back in the old cage, and do it again the next day. Second time they will probably enjoy it and explore a lot. Then the day after move everything over. It gives them chance to adjust by "trying it" before moving and can really speed up settling in time (which otherwise can be a couple of weeks of stress behaviour).
When actually moving them over you want to move everything across from the old cage without cleaning anything, and try and set things up in the same layout as much as possible. So move all the old substrate across, and spread it out on top of the new substrate you've already put in the Alaska cage.
Ifhe has a house with a nest inside, try and move that across intact, along with most of the hoard underneath the house.
So you need somewhere to put the hamster while you're swapping things over.And check evertyhign is safe before putting them in the new cage - eg food and water is easily accessible, ladders are secure, wheel can't fall over etc and nothing hard to land on if falling from roof height. If you have any pointy or particularly hard items, put them under the shelf.
A tip re toys - before you spend money on stuff that ends up being binned! (I wasted a lot of money on useless toys!). Most items sold for "hamsters" are either too small and only suitable for dwarf hamsters, or dangerous - fall apart or have nails. Tubes or tunnels need to be 6 or 7cm in diameter minimum - rat sized ones eg.
Any holes in toys or house entrances need to be atleast 6cm in diameter. 5cm at a push. The little white cat house in the Alaska is no good as a house and the holes are too small - some smaller syrians fit in it, but it's best removed. If you don't have a house he nests in already, then a cardoard box or shoe box under the shelf is best. A house that is open underneath and sat directly on thesubstrate helps them have normal behaviours - they can burrow down a bit in the substrate and bury hoards under the nest, and they can keep it clean easier themselves - it gets more ventilation. So the nest stays clean and dry and doesn't need throwing away (unless it gets pee'd in). They can often start bar chewing as well if you've just doen a big clean out and thrown away the nest and hoard! They are very particular about the nest and hoard. If it isn't pee'd in/on it can be left for quite a long time and they add bits and take bits out of it. If it is pee'd in then it does need removing, but always try and leave a bit of the old nest behind, that's dry, even if a bit whiffy - then they just rebuild it with new nesting material.
Safest nesting material is plain white toilet paper torn into strips. Never use fluffy bedding as it's dangerous - pet shops sometimes sell it just in case you didn't know. A big pile of nesting material in the cage (but not inside the house) and they pouch it and take it to rebuild the nest.
Toys - avoid anything with chains or open rung ladders, or fabric items which can be chewed and threads get wrapped round teeth or limbs. Best to stick to ceramic, plastic, cardboard or wood. Check new wood toys for nails protruding or splinters.
Rat sized toys are a good size for syrians.
Generally they aren't that bothered about toys unless it's ahidey place like a tunnel or hideout, or has food attached! Things that give overhead cover are good as although they like the floorspace they don't like feeling too exposed from above - which is why a shelf and a good sized house are good.
Hanging rat sputniks are good too - like a plastic hammock - something to sit under and feel secure or climb into. It works best hung next to a shelf where they can climb in easily. With a bit of bedding inside.
https://www.zooplus.co.uk/shop/small...ls/dens/209851
After moving them across it's a bit like going back to when you first get the hamster - leave them alone for a couple of days except for putting food and water out, so they can adjust, scent mark everything and decide what's what. Unless they show signs of wanting to come out then just leave them.
After that it's back to - don't move things around, change things or clean anything for the first two weeks. Just spot clean the pee place every few days.
Using a litter tray works well - if you put that in the place the hamster has chosen to pee - often a corner of the cage. So when you know where the pee place is, spot clean the pee and put the litter tray there, with Chinchilla bathing sand in (soaks up the pee) andput a tiny bit of the pee'd on substrate on top and the hammy will use it.
If you put the litter tray anywhere else it will be ignored! Then you just empty the litter tray every few days and the rest of the cage stays clean and dry
Hamsters are naturally very clean little things if they can have normal behaviours - they will use a toilet/litter tray and if they decide it's getting a bit smelly before you've emptied it they sometimes cover it up with substrate! They rarely pee in the nest once they've got to 8 months, if there's a litter tray and the house is big enough. Most hamsters pee in their wheels now and then.
Ongoing - you can spot clean mostly if you have enough substrate in and only need to change all the substrate every 6 to 8 weeks or even longer if a litter tray is used. And then do partial cleans - eg substrate one week, wheel another week, toys as and when needed - they oftendon't need much cleaning.
When doing the substrate, it's a good time to prune the hoard if it has got really big and remove the bottom half so it doesn't go funny. Dry hoard lasts well though. But always add a handful of new food to the hoard if you remove any, in the same place.
If you remove the hoard and nest they can start peeing on/in it to deter invaders! Then it becomes a cycle.
Hope that helps and sorry if you knew it already!