Decentralized ventilation system with 24V?

Hello,

I am building a Kfw 70 house in May and have decided on decentralized ventilation systems in the bathrooms.
Since my bathrooms are quite small, the bathtub has to be placed on the exterior wall side.
Problem: Due to the installation zone of 2.25 meters for a bathtub, I can no longer install a ventilation system here!
With 24 V, however, it would be possible again.
I have already searched on Google but unfortunately found nothing.
Has anyone of you perhaps ever found a 24V ventilation system?

Do you only have one exterior wall in your bathroom?

Yes, I only have one exterior wall in the bathroom. And since there is naturally a 1.13 meter wide window in the exterior wall and the bathroom in total is only 7.65 sqm with bathtub, shower, sink, and toilet, there is simply no space left.

What about installation above and then piping down into the ceiling of the bathroom?

It is definitely cheaper than any special models with 24V

Above the bathroom, there would still be an attic. But I thought there are no decentralized ventilation systems where piping is possible? According to the heating engineers, they always need two direct core drillings to the outside?

There is a suitable solution for every problem