Thank you already for the feedback
The windows are "normal" windows and are still completely variable. I wanted to first design the "interior" of the bathroom and then align the windows. They will probably be normal windows, 1 or 2 wings.
The stated dimensions are interior dimensions, so 2.51m and 3.65m. Only something will be built in front of the sinks for installation, which of course depends on the position of the sinks.
The dimensions of the shower are also flexible, we want it to be as spacious as possible, but without restricting the rest of the bathroom / entrance area too much. I would also be open to a completely different design, but I think V1 is the most sensible.