You can get a watch repair kit on Amazon that will have the tools to remove the pins between the links.
I’ve also had luck going to a department store with a jewelery counter and seeing if they can make adjustments. Especially if it’s a brand of watch they carry, you can always say someone got it as a gift for you from that chain of stores.
Hit up one of the poster vendors that usually visits university campuses to get some wall decoration.
A RGB lighting strip around the roof perimeter can do wonders for setting the mod of the room.
If you have want to have people in your room to hang out, consider getting a futon instead of a bed. Won’t do your back any favors, but will be more functional during the college years.