[Ria P]

Hi and welcome to HC!

Straw isn't suitable for hamsters because its too coarse and stubby. I'd replace it with paperbased substrate like Kaytee clean and cozy and add torn up strips of plain white toilet paper for nesting material. Hamsters like to be cozy and comfortable.

What exactly happens when you're in the same room as him? You say that he doesn't like it. How does he express that?

He doesn't sound happy and maybe he's trying to tell you that something isn't right in his environment.
Does his wheel work ok and is it big enough for him?
Does his water bottle work ok?

You say that he's chewing the plastic of his cage. I'd give him a Whimzee dog chew. Hamsters love those.

If you have a playpen or save area then you could get him out of his cage by putting a treat into a mug or jug and let him walk into to transport him in and out of the cage but cover the top while in transit. Put some toys and hides in the playpen as well. Some hamsters are quite diffetent when out of their cage.

A photo of his set up would help in case there's anything that could be improved or tried to help him feel more settled.

Moving his things around isn't a good idea. I did that when i first got my Syrian but stopped that after he threw a few tantrums. Replacing an item he doesn't like or use with something else can work while trying to find out what he does and doesn't like. Its necessary to tailor a hamster's habitat to their needs and likes which can take a while of observing and getting to know the hamster.