The built-in wood design of the adjacent cabinet is clean and modern. So as not to waste the under stair space and not interrupt the clean spare look, I would put in a blind door that matched the zig zag of the stair, with barely visible hinge hardware on the left side (probably will need at least two and maybe three hinged doors), then matching the exact stain and wood, create a blank slate look, flush with the cabinet and wall trim. And, there, hang a piece of artwork, or wall sculpture. Keep in mind, when you do this, the white of the zig zag stair will pop, but I don't think that's a bad thing.

I think it totally depends on two things, 1 The available space 2 Your religious belief. Someone who is very religious may try to squeeze a separate space even in tiny flat, while someone who is not overtly religious may just have a small corner with Idols in spite of being in a position to have a separate room.

Looking for places that supply handles for drawers 4" in black metal in Mumbai

Old designed wooden wall units.