Ideas for dividing and planning an apartment

Then I would go for the modern tankless water heaters, they are very efficient and take up significantly less space. Remove the bathtub and install a nice, large shower with a tankless water heater.

Kitchen: around the corner, not a U-shape, only in the niche and along the lower wall; dining table towards the wardrobe and between the kitchen and living area. Maybe divide the living area into zones: large couch for watching TV and small reading corner.

would this work here? The dining table is 120cm in diameter.

With a 120cm diameter table, no one can get out of the corner anymore

What are your requirements for the kitchen?

Fridge. Dishwasher, sink, 60cm hob with oven below?

actually just basic equipment. When we are there, we usually eat out. If the weather is too bad, food is mainly eaten cold in the apartment. An oven should still be available. would there be more space with a corner bench?

The 7cm interior walls are probably neither load-bearing nor bracing; I suspect they are built from solid bricks turned on their narrow side. Nevertheless, I see all the walls on the right side of the plan remaining untouched by your considerations, although the boundary line between the "Bad" and "Eltern" could most likely reshuffle the cards for a redesign of the bathroom. Otherwise, for a "holiday apartment" of this size, it would seem obvious to me to create a room for personal belongings (separate bedding, etc.) in order to be able to rent out the still not small "rest" simply on a temporary basis.