All-inclusive bathroom on 8m²

Roughly calculated 750 - 30 cm -30 =660

A bit too rough :)

Yes, I made a mistake there, but where is the installation wall for the shower and the toilet? It must not be on the exterior wall, so a facing wall that would take another 20 cm.

Even better, skip the shower and shower in the bathtub!

If you stopped aging upon retirement, ok - but: bathtub logically excludes "floor-level" (with regard to the threshold). When you're young, it doesn't matter yet ...

From my point of view, there is also no truly aesthetically pleasing solution in the area of "Duschabtrennung auf Badewanne".

Well, a 60cm passage to the shower is not barrier-free either!

Therefore, either or! Shower or bathtub but not both.

If you stopped aging upon retirement, okay - but: a bathtub logically excludes "floor-level" (with regard to the threshold). When you're young, it doesn't matter ...

There are now quite a few manufacturers offering shower bathtubs.