Emergency bathroom planning, plan quickly

Here are a few other ideas,....

the first picture with the toilet but not around the corner, rather on the side wall is my favourite... however, it is so that it seemed very tight and strange on the construction site... on the plan I like it

Our bathroom is laid out almost the same. We have the toilet and sink mirrored on the side below the door. The shower and bathtub form a "front" for us, with built-in protrusions between them that provide storage space.

I would actually leave it like that. The other designs feel very cramped and partly dark, and in some cases there is too little space to move around freely.
As already mentioned, with 140cm you need a door on the shower anyway. I would let the wish (which I can understand) remain just a wish, in favor of a bright, more spacious-looking bathroom.

Our bathroom is almost laid out the same way. We have the toilet and sink mirrored on the side below the door. The shower and bathtub form a "front" for us, with masonry projections in between that provide storage space.

I would actually leave it like that. The other designs feel very cramped and partly dark, and there is sometimes too little space to move around freely. As has already been said, you need a door on the shower anyway at 140cm. I would let the wish (which I can understand) remain just a wish, in favor of a bright, more spacious-looking bathroom.

Yes, the problem is just that since I am coming up with this change request too late, the situation will be that I have to sign that the screed might crack. Otherwise, they would lay the toilet drainage above, so that I would have a boxed-in wall along the window at the bottom... I don't want a boxed-in wall even if it is deep, I think it looks ugly... and I can't estimate how it will be if I sign that the screed might crack... that is my fear.

Then I find the shower oddly detached from the tub... but I was thinking of taking a square shower to make the corner a bit rounded...

So the main problem is the toilet, which I cannot weigh the risks that I sign for.

I wouldn't risk that either. The sink isn't that far from the door anyway. In addition, in the current plan, you still have space for a tall cabinet between the shower and the sink. I don't have that because of the continuous tub-shower wall, and I really miss it. Maybe the design isn't so bad after all? I think it feels very spacious, especially for 8 sqm.

I would probably do it like this:
Corner bathtub and toilet in the middle of the [Vorwand].

I believe that if you draw it to scale, the corner bathtub extends much further into the room and then it could become tight with the corner of the shower wall.