If you want to do it so that part of it is fixed, why don't you just install a drywall partition with a normal door that opens outward like the bathroom door.
And, vertical blinds, just google it. I had them for years in my old apartment for an almost 3 m wide niche. Split into two parts, drawing together towards the middle, you could wonderfully access my "junk storage space." There was a hanging rail for jackets/coats, Ivar shelving for all sorts of small stuff, etc.
For a friend, we realized this in her small hallway 3 years ago. She needed easily accessible storage for shoes, vacuum cleaner, supplies, etc. So we equipped the hallway niche with Ivar shelves and a place for the vacuum cleaner, etc., and simply put up a vertical blind curtain over 150 cm wide from ceiling to floor. It always looks neat, can be color-coordinated really well, and can be purchased custom-made at a low cost.