you need to consider thermal needs, privacy issues, light control, noise control, decorative preferences, size of window, room available around and above window, shape of window, budget...that is why a professional window coverings expert is the best to assist.

I agree with Mel N. It's a relatively closed space and I think with the frames and the light fitting, less is more. An obvious curtain rod would be a step too far I think - pleated curtains on a hidden track would be how I would go.

I note you have blinds already.We too have blinds and my light sensitive husband found the cracks of light down the sides woke him early. I stumbled over a place that sold ends of current fabrics at very reasonable costs so bought enough linen to match the wall colour and lined it with blockout lining.I made each curtain 90cm wide although once they are gathered on the 30cm long track they are full and generous looking. (so they only cover the edge of the blind) and have totally cured our light problem for well under NZ$100. We bought a metre of track and two fittings that allowed us to make two 30cm rails, using a hacksaw to cut it down. I too agree, match the wall colour so you have a good plain backdrop for duvets and accessories in the room. I'd be hesitant about a feature wall in a small room,may close the room in.

Yes, the steps are a small challenge. My suggestion is to work with that angle of the steps. If you would like full block out curtains, angle the hem of the curtains with the steps. With the width of the opening, and having the curtains pull to each side from the middle, there will be quite a bit of bunching. So I would suggest one curtain fitted across left hand window. Then the remainder of curtains pull from the door opening panel, back to the right. Depending on our much 'block out ' you require, I think the following product from luxaflex looks your style, but would not bunch up on the sides as much as traditional curtains. https://www.luxaflex.com.au/products/blinds/lumishade/ Still working with the angle on the steps.