Answers

Bookshelf or a closed cabinet?

Open shelving if the room is small and what you own is worth looking at. A closed cabinet if it is not. The choice is less about storage than about how much visual noise you want on that wall.

Open shelves keep the wall visible behind them, so a small room reads as larger. They also show everything, which means the wall only looks good if the contents do. Books work. Chargers, folders and boxes do not.

A closed cabinet hides all of it and gives the room a quiet surface, but it reads as a solid block. In a narrow room that block can be the difference between cosy and cramped.

The mixed answer is the common one: closed at the bottom, open on top. It hides the ugly two thirds and keeps the wall from feeling heavy.

Height decides more than people expect. A unit that stops short of the ceiling leaves a shelf of dust and dead space; one that reaches it reads as built in. Worth previewing both against your actual ceiling before ordering.