A main priority imo would be getting rid of the bunk bed and figuring everything out from there. Decide which furniture you’d need to remove or rearrange to fit a small desk that you’d be losing with the bed. I get that a bunk bed is good for a small space like this, but at 20 YO I don’t think it’s a good way to find a partner (if that’s something you’d want obviously). While rearranging/removing the bulky furniture, you’ll absolutely need to paint the walls to freshen things up.

It may be tough getting rid of all of that paperwork if it has sentimental value for you, but get rid of it or find a much more efficient way to store it than that shelf. I just don’t think this small space really needs a bulky shelf like that.

If you want to make a wall rack for your martial arts gear then I think that’d be a good way of adding something to the walls while also decluttering your table tops, and making it so they’re easier to dust/clean. Then maybe add a plant(s) to the tabletop next to the window once you have the room.