WHAT?????? Sorry but IMO any window tha you can't see out odf is horrible .SO post some pics of the window areas and the view outside . I like as much light and views as possible from evey window. I think if I understand what you are planning a custom made piece of stained glass is probably the way to go.

Get an stained glass window if that’s what you want. I guess what you are asking for is a scrim used on movie sets so there is a ‘view’ out the windows, don’t think that will work applied t9 the glass. Fix the view, get stained glass, or get shears/blinds/shades

I wouldn’t go to that expense. There are companies that can apply removable “frosting” type materials. Maybe start with that if you don’t want blinds/ curtains….

Yes, hang a stained or leaded glass window inside your picture window. If it’s very large you could hang a triptych of framed windows. They make stained glass film that you could apply directly to the glass, or you could apply it to framed glass to create your own stained glass window to hang.

Depending on what is outside the window, you could also construct a screen or arbor in front of the house, fairly close to the window, plant it with beautiful plants to grow on it and look at that instead of the biew beyond.

You don't describe your room (height, size, etc.), but contact an architect. Maybe clerestory windows or something would be a better choice in your situation.