Bathroom window (looking outside yes / looking inside no)

Then you have already found the solution for yourself. For me, it would simply be nothing to constantly open and close, and you would have to be able to switch from the bathtub as well (which would also be no problem to realize). This should not be a judgment either. I just wanted to make you aware that this might be impractical. Although, with our bathing habits (twice a quarter), it would probably be easy to bear. How is it with the other bathroom uses? Is the blind always down because people can see in?

Roof windows!

Unfortunately, there is no sloping ceiling in the room for that

How about pleated blinds? They have the advantage that they can be positioned variably on the window. Roller blinds and Venetian blinds can always only be lowered from the top.