Is high ceiling height possible with controlled residential ventilation?

It is often done, but there are shell builders who do not like to see that - the structural engineer has to check whether it is carried out correctly. However, it is then too cumbersome for the shell builders as it leads to waiting times for the concreting.

But I would rather have a conversation with the shell builder and discuss the topic than give up about 10cm of knee wall in the upper floor under the given conditions (450cm exterior wall height and 270cm interior height on the ground floor).

Oh man, you're right. I wouldn't have thought of that either. ops:
So plan controlled residential ventilation into the concrete ceiling, hang the ceiling "normally" and extend the outlets so that they are in the suspended ceiling.
Is controlled residential ventilation in the concrete ceiling something that is often and standardly done, or so unusual and difficult that it becomes expensive?

It's nothing special. Some also install flat ducts on the ceiling, which is also an alternative.
What is unusual, however, is the subsequent suspension, as there is no reason for it (unless you like to spend extra money).

Or one wants a slightly different light installation

I still can't imagine how recessed lights are installed in the concrete ceiling. That means I need holes in the concrete. And how does it work with the cables?
Besides, then I am stuck forever with the positions of the lights.
Therefore, I am currently still thinking about suspending the ceiling.
But when the time comes and proper planning starts, I have to discuss it with the respective construction partner.
For now, it was just about how the [Kontrollierte-Wohnraumlüftung] could work.

I still can't imagine how recessed lights are installed in the concrete ceiling. I need holes in the concrete for that. And what about the cables?

There are special boxes that are mounted on the ceiling panels before they are poured with concrete. The cables are usually also laid in the ceiling before the concrete is poured. You won't see anything of that later.

Besides, then I am stuck with the positions of the spots forever.

No. If you want a different arrangement of the spots in 40 years, you can still install a suspended ceiling. But I wouldn't bother with that work now. Once the holes for the spots are drilled in a suspended ceiling, moving the spots is also associated with high effort.