Tiled shower floor - sooner or later trouble due to silicone joint?

you should have installed the drywall partition so that it aligns with the shower tray ;) You can also see it on your plan.

In what way? Because of the extension or the storage on the floor? It can't be done differently since the apartment was already in shell construction and the riser shaft is here. The shower was actually the toilet, so even more wasted space. Of course, this segmentation bothers me too, but that's where the door goes.

And further? I don't think you can easily find a shower tray with the dimensions 103-105*100. The solution would clearly be tiles.

The rest looks quite nice. But is the washbasin really supposed to be implemented like that? Instead of the more or less useless corner in front of the window, I would run the washbasin countertop there. The sink itself can stay there.

But 100*105. Aside from the fact that the partition wall is totally off. That is just a block.

The rest looks quite nice. But is the washbasin supposed to be realized like that? Instead of the more or less useless corner in front of the window, I would run the washbasin countertop in there. The sink itself can stay there.