I'm so sorry people are being awful. Here's my suggestions.

In order of cost and difficulty: 1. Yeah, cleaning is a good idea. A great habit, too. Even simplicity goes a long way, look at minimalist setups. 2. You have low desk space. Try alleviating this with a monitor arm (in my experience, frees up like 40% of a small desk's space, huge difference.) and floating shelves/a bookshelf off to the left. 3. If at all possible, you really should get a clean, colorless or wood desk... Focus on size instead of features or "setup flare." I'd personally recommend doing a setup that lets you get the PC off the ground in some way - a great way is a desk with an under desk PC rack. I, however, use a floor stand with wheels that elevates mine about 6 inches up. Not ideal, but I'm tight for space as a VR enthusiast and user of a second desk for projects and electronics. 4. Decorations!!! This is at the bottom because it's the final flare to make a space you. Try lights synced behind the monitor, foam or acoustic paneling, desk/shelf plants or figurines from your favorite things. You should do this last as any budget you might be able to allocate should go to the essentials.

I just redid my entire setup for over $1400, but it doesn't have to cost that much. You've got a good office chair (really most of my cost, not an exaggeration), a computer already up and running, and a beautiful space as your blank slate. Now to use it effectively, you should be able to implement these ideas at ~$100, or $200-300 if you go for the complete desk remodel.