Bathroom layout 8.5 m², how can it be improved?

Hello!
We are moving on to the execution planning, and during the bathroom sample selection for the bathroom in the sales unit, it became apparent that the shower enclosure as planned would be an expensive affair (because it sits on the edge of the tub and also needs to be extended down to the floor next to it).
I'll attach the floor plan as the architect designed it and an idea from me. The advantage would be that the shower would work entirely without an enclosure.
It's done in pencil, but roughly to scale. +/- a few cm.
What do you think about it, or does anyone maybe have another idea on how to better separate the tub and shower? Are the passages reasonably sized or will it be a tight squeeze? (There is another shower bathroom on the ground floor for family use). I have intentionally drawn the toilet quite large – what is the minimum distance that should be maintained from the tub?? The washbasin is also quite large at 100 cm, but many people like such spacious washbasin furniture.

Looks very tight. Note that several centimeters are subtracted everywhere for tiles and plaster.

Your toilet has no wall behind it. Is that intentional? Where is the cistern located? It will be a narrow passage.

I would stick with the old design. Unfortunately, I don’t understand the additional costs at all. The shower wall will be provided and then the tub pushed up to it. There will be a silicone joint in between and that’s it. Half wall and mounting on top? What kind of nonsense is that supposed to be?

You don't need a partition on the tub. Why?

I also consider your passages to be bold. Even the person standing at the washbasin is in the way, the toilet sitter is in the way, etc.

I would try placing the tub next to the door. Next to it, that is on the left side of the plan, the toilet and washbasin... but the proposal isn't really satisfactory either. The first proposal from the BU makes sense and is clear. It also doesn't cost any extra, as it's not a special feature.

That doesn’t cost anything anymore either, since it’s not a special feature.

Then you didn’t know yet that many general contractors (most?) have completely removed all shower enclosures from their construction specifications.

But on the subject:

Shower enclosure on bathtub = expensive, as it is custom-made
Shower enclosure beside bathtub creates an unfavorable gap, since the frame is thicker than the glass. From inside the shower, you can always look through the glass into the dirty gap, also not great! Silicone joints all around do not make it better, as the shower wall on the outside of the bathtub box gets condensation --> growth etc.
An inexpensive and practical solution would be a corner shower with an appropriate distance between the shower and the wall, where, for example, towels could be hung. However, that’s not really attractive either.

Between a rock and a hard place