Controlled residential ventilation (heat recovery) + air well + exhaust hood and "independent" chimney

Yes, discuss this with him. I assume he simplified it and it should be 100-110mm thermal insulation (WLG 0035 or better) and 30mm tacker system (WLG 0045). Specifically address the problem of missing thermal insulation under the pipes and possible condensation water.

It will become a topic of conversation, especially because the energy consultant also declared the minimal BP as necessary to achieve KFW55.

[*]10cm WLG 035 insulation + 4cm impact sound insulation WLG 040 + 25cm Steuerberater floor slab

Ceiling because you can then:
freely place the valves and never block them with anything.

If in the floor slab, you weaken the insulation at one point where there is continuous ground contact.

In the filigree ceiling, only the insulation to the lower rooms is weakened.

Here is a picture of the implementation in the intermediate ceiling. Unfortunately, the spacing in the blocks of the lattice girders was too narrow, so they had to be bent upwards. A terrible job, but the structural engineer gave the green light.