You don't have a room or configuration for a walk in closet. Use the wall opposite the bathroom end of the room for a reach in closet, put the bed facing the window wall left of the entry. Your responses will be mostly USA so convert that drawing to inches and feet for us laggards. PS........ I'm guessing too.

I agree...the far left wall has no windows and will give you a very nice @13’ reach-in closet which can be designed in several sections to include all your clothing shoe and accessory storage.

That left wall is perfect for Ikea Pax closet and there is nothing wrong with some empty space .

I'm trying to understand exactly what the issue is here. You write that you feel the space isn't being used efficiently but you don't say that you need more storage space. If you don't need me storage space then wouldn't it be nice to have some space to make it feel more spacious? If you do need more closet space then I agree with creating a reach in closet. Please think about what you need and will use before creating a whole project just to use up space