Planning main bathroom with pre-wall installation

Variant 5 is a winner for me. I find two different shelf heights at the tub annoying and think it’s better when it’s flat all around. The "niche" next to the toilet I would emphasize with a bold accent color or a mosaic wall, but these tiles would have to be repeated somewhere else, e.g. behind the tub. Then you would have the accent on the actual back walls.

As a man who pees sitting down, I wouldn't see the difference between versions 6 and 1 because I don't have eyes in the back

True, but if you stand in the room, it might be noticeable, but only if you look very closely

Merciful goddess – just extend the tiles all the way to the box between the toilet and the window, otherwise it looks stupid. How can such an aesthetic mistake come to mind when you are otherwise a symmetry fanatic?

I actually want to tile as little as possible and therefore originally didn’t want to tile on the short side of the bathtub. So I thought it would look better not to tile on the opposite side either (i.e. the prefabricated wall next to the toilet). Like in the attached example picture.

But maybe you’re right and in the case where the prefabricated wall next to the toilet eventually ends, it might be better to tile.
Then only up to the height where the open part begins (could be about 90 cm in height)? I would then do it consistently at this height behind the toilet and behind the bathtub as well.

Option 5 is a winner for me.
I don't like having two different shelf heights at the bathtub and think it's better if it's flat all around.
I would emphasize the "niche" next to the toilet with a bold accent color or a mosaic wall, where these tiles would have to be repeated somewhere else, for example behind the bathtub. That way, the accent would be on the real back walls.

I have also noticed that two different heights might look odd. If the bathtub directly abutted the raised shelf, it might be something else, but as it is, there is first a "shelf" with the bathtub faucet and then another shelf. Above all, the raised shelf has a different depth than the pre-wall behind the toilet, which means an additional corner. Maybe it really looks better to have just one large shelf.

I also like the "niche," although I would also prefer to have the toilet brush etc. hidden in a recessed module, which the continuous pre-wall would allow.

Yesterday, another idea came to me that I would like to discuss.
The washbasin is supposed to go on the side opposite the toilet, next to it there is another pipe box for wastewater + ventilation directly at the corner of the interior wall/exterior wall of the gable side. Of course, this pipe box is also disturbing.

Would it perhaps make sense to move the entire gable wall forward? (see image shaded area) You can then also install niches at various points (under the window, next to the toilet a bit higher) or flush-mounted elements (next to the toilet).
The only question is whether the window would then appear recessed too far back. The windowsill would of course be extended all the way forward; it would then be quite deep. Unfortunately, I can’t imagine it at all.
With this solution, of course, all corners on the gable side would be avoided and it would look like a “normal” wall, except that the window would appear installed very deep.

I actually want to tile as little as possible and therefore originally did not want to tile on the short side of the bathtub. So I thought it would look better not to tile on the opposite side either (i.e. the false wall next to the toilet).

Apart from the fact that you can’t guess that – especially not because the slope is even tiled in your pictures – you are taking the nonsense to the extreme if, for reasons of symmetry, you "consistently" apply a defect on one side equally to the opposite side.

Would it then perhaps make sense to extend the entire gable wall?

Read that very slowly again yourself. You want to build up the entire wall flush with the hated boxed-in areas – are you by any chance taking the stuff in pill form that’s smoked in the town hall of @goalkeepers building community?

Apart from the fact that you can't guess that – especially because in your pictures even the slope is tiled – you are taking the nonsense to the extreme when you “consistently” apply a defect from one side exactly the same way on the opposite side for the sake of symmetry.

Ok, I didn’t think it looked tiled in the pictures – it’s just a 3D simulation without wall fittings. On the washbasin side I would like to tile behind the washbasin, height 1.20 m. Also in the shower (height 2.2 m or so). On the bathtub/WC side I would like a different tile height than 1.20 m – otherwise it looks too uniform or “bathtub-like.” In any case, the slope will not be tiled; I was thinking about 90 cm to match the height of the windowsill. And I don’t see it as a defect if the short side of the bathtub is not tiled; I believe the days of massive tiling are over. But I’m still considering it, possibly on this short side up to 90 cm as well. And of course, next to the WC it’s also possible to tile the pre-wall up to the cutout – so again 90 cm high.

Read through that very slowly once more yourself. You want to fill the entire wall flush with the dreaded boxing-in – are you by any chance taking the stuff in pill form that they smoke at the town hall of @goalkeepers’ building community?

What’s wrong with that? That way you get a flush wall without projections, visible pipe boxes, etc. Only the window is somewhat deeper – whether that stands out negatively I can’t judge right now, you’d have to see it in real life. Even the pipe box to the left of the washbasin is already disturbing; overall I find the whole gable wall with its constant projections and recesses extremely restless. Which is completely eliminated by the flush pre-wall.