Where did we lay the "infrastructure"?

Hello,
I would like to know what options there are for laying water and electrical lines.

Regarding electricity, my understanding is that the best option is to install empty conduits into the precast concrete slab before pouring the floor slabs, and then these are encased in concrete. If there are multiple conduits bundled together at one point, that area is reinforced with additional steel mesh.

Water pipes should not be embedded in the ceiling because they may need repairs at some point. Instead, they are laid on the concrete slab and then the chaos begins... I have heard numerous methods here, and some of them are called botched work in forums.
For example, water pipes are laid on the concrete slab, and the impact sound insulation around the pipes is cut out where the pipes run. After installation, the cavities are filled and the screed is laid above. The underfloor heating is then installed on top of that. Some people say this is botched work because the insulation is interrupted. But I also know someone who did it this way and said it doesn't make a difference.
So how is it done correctly?
Where is the best place to run the lines for heating and drinking water?
In some rooms I am also considering wall heating, but in some like the kitchen it is not possible because all the walls are fully occupied.

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If you only want to answer my question, you can skip the block in brackets, otherwise please read:
[ No, I will not make my floor slabs myself. No, I will not draw the plan myself. Yes, I know that a qualification is required for that. Yes, the whole thing will be calculated by a structural engineer. Yes, the plan for the electrical installation is made by an electrician. Yes, the plan for water and heating is made by a heating engineer. Yes, in the end the static calculation will be checked by a civil engineer. The whole thing will be planned by a professional, but I would like to know beforehand what the proper procedure looks like so that I can discuss the options with them.]
!!!

Apart from ceiling outlets and spots, everything was installed on our finished raw ceiling. Above that, there was actually always enough space for 2 thin layers of insulation. Our building savings contract had no problem with that, and so far I have not noticed any differences on the screed either.

On the floor or under the ceiling. There is no right or wrong. Depending on the construction, wiring, etc., one, the other, or both can make sense. For example, we supply the kitchen from the basement with a ceiling penetration. Most of the cables are under the ceiling. But that also depends on our floor, which is installed with 250°C, and we are hanging the ceilings anyway. The electrical wiring is mostly in embedded empty conduits (concrete walls).

If the ceiling is not dropped, boxes with LAN cables for WLAN access points should be provided. The number depends on the floor plan.

The easiest way is simply to lay everything on the raw floor and then "mess around" as you wrote. That's how most house builders do it.

At our place, the concrete ceiling of the ground floor and upper floor provides the electricity. Under the screed in the insulation are water pipes, heating pipes to the distributors, and from the distributors some underfloor heating supply lines for more distant rooms. Ventilation ducts are in the concrete ceiling and in the insulation of the top floor ceiling.

I have often seen electricity on the rough floor in others as well.