Interior walls in drywall construction

Thank you for your impressions. That reassures me a bit! :)

As an alternative, the following is meant:
1. Drywall partitions instead of solid interior walls (11.5) thickness
2. Solid interior walls with additional crack-bridging mesh. However, this is not recommended.

Interior walls made of the same stone would not need the mesh, and lightweight walls would need it. Unfortunately, as I said, I do not see any plan of your house here, so it is difficult to address the question. For solid construction, it depends on what they are supposed to be made of and what the exterior walls are made of. Aerated concrete with 7.5 or 10 cm thickness already saves considerable weight compared to 11.5 cm calcium silicate brick.

I wonder why the intermediate ceiling just doesn't get thicker....

Walls where there are no walls with the same alignment beneath benefit from beams. Thicker floor slabs are also heavier and therefore need the beams even more. As I said, one could respond more creatively if one knew your house. From

Since we have a very wide ceiling span in the living room,

I conclude that it is not any of the catalog designs known to me.

Walls where there are no walls with the same alignment beneath are happy about support beams. Thicker floor slabs are also heavier, and therefore require the support beams even more. As said, one could respond more creatively if one knew your house. Aus

By the way, that’s exactly how it was done for us as well, since we didn’t want a wall originally planned in the basement. It was no problem at all, and now we have the entire kitchen/living room area without a load-bearing wall.