Floor plan design of a semi-detached house for large families

Children at night in the utility room? That needs to be explained to me!

Not to me!

I would plan a living room that all family members can use together. Give it a space where children can play and the rest can communicate.

Yep.
Furnishing options with and without a play corner.

I would also suggest the exterior walls for the living spaces as Kaho has drawn them. More light where it is needed. Zoning into living and working, later living and sleeping. Too many walls can, however, also restrict where they don't have to, kaho

too many walls can also restrict where they don’t have to, kaho

You mean already too many walls? We'll tear them down - sure. I’m also in favor of fewer!
However, a separable kitchen was requested - we still need to do some convincing that the walls should come down.

As mentioned, I consider the maintenance shaft to be exaggerated, i.e. the reasoning is understandable and absolutely correct, but on a different scale than a single-family or two-family house. With heavily calcareous water, on average you break open a wall every 60 years or so. But an installation wall may be worth considering. For that, as a placeholder in the floor plan, a load-bearing wall is also suitable in terms of thickness.

The modular dimension of 62.5 cm as a planning framework can nowadays practically be ignored. Because this only results in situations where rooms are planned either too narrowly or too wide in order to stay within the grid. I would apply such a planning grid at most to the exterior walls and proceed flexibly at least with non-load-bearing partition walls.

You mean, already too many walls? We'll tear them down - of course. I'm also in favor of fewer!
However, a separate kitchen was requested - we still have to do some convincing to get the walls taken down.

... in the living room