Exhaust air and supply air one above the other?

Hello,
we are just about to submit the building application. I still have some concerns about the ventilation system.

My architect says that the exhaust air can be placed at the bottom and the supply air above it (2m distance).
My fear is that the bad air, which is known to rise, will be sucked back in.

Am I right to be worried or is that nonsense?

Alternatively, the exhaust air would run along the ceiling to the end of the room. However, that would probably take up space for shelves and is not so compact.

Going around the corner is not possible because it is a room in the middle.

Thanks in advance for your opinions.

Regards Christopher

Actually, that's not such a big deal... but we also have it in the bedroom (and directly) - works better than expected. Is that a central system?

Not in the rooms. The exhaust and intake air that goes from the utility room/HAR to the outside.

Exhaust and supply air that goes from the utility room to the outside?! No ventilation system, except for a decentralized unit in the utility room? Or do you mean the heating somehow?

Completely normal KBE system. Every house has the exhaust and supply air around the utility room.

And why not side by side? That’s how we have it. Outside, there are no "intake towers," just two 90-degree bends with grilles, facing in opposite directions.