I also have a window like that in our shower - it may, but doesn't normally get wet from the shower. I have put in a thin venetian blind in white (made from plastic) very cheap, under $5. I am in process of making an puffy austrian blind to hang above the window, for a bit of colour I am making it from a shower curtain). It will be there for looks, I may never pull it down. The venetian gives privacy and blocks the light a certain amount.

With tilt and turn windows I can only think of two options, either face mounted shutters to the actual window, which the fabricator might offer, or a rod hung on the face of wall above the window opening, to avoid the window catching on them. A track sheer or drape will work aesthetically, but practically?? Presuming when the windows open, so too would the curtain, it only matters at the end of day when you want to close up and have privacy, so perhaps a holland blind (pull down) so it's least conspicuous.

although i always prefer curtains a 6m wide opening will need either a very light fabric or about 1 m either side to fully pull back to each side where blinds would be able to be raised completely above the window (assuming there's somewhere to attach them) discuss options with a window covering specialist as there are some new options that may suit you better..i also suggest to clarify flyscreening, security and ventilation options for your very wide opening as we found a more flexible and cost effective result with a door height panel of stacked awning windows next to a wide section of stacking doors so that we can open the window for ventilation without opening the doors

It depends on the outlook, the privacy required, the orientation, and how much heat it gets from the sun in summer. I would suggest living with it for a year to understand exactly what you need. As the windows are non-openable I would suggest avoiding anything that requires maintenance such as timber battens, or anything that provides suitable nesting potential for birds, as the droppings from nests can make an awful mess. If money was no option I would consider adjustable metal louvres, perhaps mounted vertically, that could be opened and closed depending on the time of year. Resear ch Vergola. Best of luck Dr Retro of Dr Retro House Calls.