No where near enough info to even know what the sapce is used for .

What will be the proposed function of the space?

No Context Shall Equal Mystery Meat

It's a bedroom? A sitting room? What will be on the wall next to the door? A tv ?

Why a "slat" anything?

I would not do lower cabinets and add any horizontal lines since it is only 67" tall. Do not do cupboards on the bottom with a horizontal line and shelves above. That will only accentuate the short ceiling height. All your inspiration pictures are full height bookcase or cabinet so I would suggest you do a full bookcase on one side and a cabinet on the other then trim out the door and add baseboards like normal since you may be adding a bed or dresser to that empty wall space.

Make the trim and baseboard as minimal and hidden as possible in this short space. You need to accent here. Paint the walls and ceilings the same cllor and it will feel larger.

What are you using the room for? What will you store on the shelves and in the cabinet?

Adding more photos and floor plan. It’s a bonus room above the garage that will be a music/tv hang out room.

Your question had an orientation

Mine would be why are you worrying about that wall, You will need a coffee table : )