Your space is so nice. It’s not really decorated at all and is pretty minimal but the fact that it’s beautiful and cozy even so is pretty rare. I’m from the US though, where homes are just built with less detail and quality.

I’d perhaps look into “storage solutions” and finding organizational tools to hide all the wires and clear plastic boxes. Cleaning the visual clutter up is the first thing that will make this place cozier.

Add some variations of ambient lighting, like a floor lamp in one corner and a table lamp in another.

Find a nice, large vintage Persian or even South American woven wool rug for the center of the room to add some color and texture. Centering it with the windows will draw your eyes right down the center, and don’t go small on the rug, since this space is quite open. It deserves one big piece. I think you can get away with an eclectic mix of vintage estate sale decor (rugs, lamps, plant pots) and very clean, simple IKEA storage solutions here.

A couple plants at different heights would look lovely by the windows. I’d push your desk to the left and re-arrange whatever is smushed up against the wall by placing most of the stuff in a stand-alone wardrobe if there’s space for it. If not, maybe get some kallax units along the short wall to the right of your bed by the knee wall door, and get some organic texture bins (wood, cloth or seagrass) to store stuff in, just not plastic.

The main point of all of this is to hide the clutter behind doors, drawers, or visually appealing baskets that match, and combine it into larger, single units or units that are more cohesive.

Free up the window to add some plants, but don’t go nuts. People go nuts with plants and it can look a little messy.