Thank you so much for showing us his set up

He seems to have quite a few nice things to do in there and it looks cosy and is a reasonable sized cage

There is the odd safety thing though and that might also explain why he might have caught a nail on something. Sorry to say but the wheel isn't safe. The design is not that safe and he could get a leg caught. It is also too small for a Syrian hamster.
Sorry to be the bearer of bad news but you need a new wheel asap! They do best with a 28cm diameter wheel. He will love that! They can run so much better in them and also it means he can run with a straight back. If the wheel is a bit small it can start to cause them back pain if they're curved when running. The trixie 28cm is about one of the cheapest wheels you can get at £12 and it's an ok wheel and perfectly safe design! Our Syrian has one in his playpen and loves it. I'll link it below.
Other than that - maybe add some more substrate to his cage

Ideally at least 4 to 6" deep as they like burying their hoards and digging. The idea is - the more substrate you have, the less they need cleaning out. You just spot clean - which is taking out the odd handful if it's getting a bit soiled, and replacing it with a new handful. You can go on like that for weeks or even months, without needing to change the substrate, especially if they use a litter tray as then the cage stays clean and dry. Their poops aren't really dirty - they're like little hard seeds. So don't worry about those unless there start being quite a lot and then spot clean them out.
There are also many alternatives to wood shavings these days. Kaytee clean and cosy is popular and works out quite economical. It's a compressed bale so fluffs out. Sadly pet shops do sell wood shavings and in the Uk they are not too bad as they have to be kiln dried by law to remove most of the phenols (the pine smell). The phenols are bad for hamsters respiratory tract.
But next time you get some substrate have a look at Kaytee clean and cozy. Amazon sell it. So you're not buying everything at once. Hamsters love it too as it's nice and soft and they sometimes take some for their nest.
By the way if you were sold any kind of "fluffy bedding" or synthetic type material for nesting that is mega dangerous! There are a few petitions to ban it. If you have that you need to bin it asap! The safest nesting material is plain white toilet paper, torn into strips. Hamsters love that too and they pouch it and take it to the house to build a big cosy nest.
He looks to have a good house in there and a nice sisal tunnel. Am assuming he's not a chewer or the hammock would have been chewed but unfortunately the hammock isn't really safe either. Even if he doesn't chew it, he could get a leg trapped. Plenty of hamsters end up hanging by a broken leg unfortunately! Any kind of fabric is unsafe as string or threads can't be digested if chewed and threads can get wrapped around feet and cut the circulation off or wrapped around teeth. So always best to avoid anything made of material. Wood, ceramic and plastic are safer (and there are some grass hammocks that are ok).
Sometimes we know our hamster and know they're not a chewer and would be ok with say, a fleece hammock that's well made with no loose threads or fluffy filling. If he's been ok with it so far then don't worry too much but it might be an idea to replace it with something safer.
So basically - more substrate, new wheel, replace hammock

. Some people will probably say you need to upgrade the cage to a bigger one as well. But if he's been perfectly happy in there and has plenty of out of cage time, I wouldn't worry too much right now. It looks like the Grosvenor cage which is just about on the minimum cage size recommended for a Syrian. Having said that, they always appreciate more space!
Changing things around is a debatable point. Generally hamsters like things to be the same - familiarity. And it can stress them if things get changed around. They accept something new being added but don't seem to like it if things are in different places.