I cannot imagine that there is no installation shaft. Imagine if everyone could do whatever they want. There would be a mess with the wastewater pipes, which would very likely be unacceptable, since too many corners and bends must be avoided. The same applies to load-bearing walls that support the upper floors.
Could it be that you are taking "everything is possible" or "you can do whatever you want" too literally?
Regarding the wastewater shafts. It would be preferable if the toilet upstairs on the right stays there; the kitchen can be placed in different locations. The bathroom downstairs as well. Of course, this means further pipeline routes and costs depending on the case.
Regarding the load-bearing walls, in the end the building still has to stand; the structural engineer will have to recalculate this. The "most problematic" is the living room, which has a large span and only supports along the entire left front. But in consultation with the architect, we will first draft the various variants and then have the structural engineer recalculate everything again or, if necessary, plan for a beam...