Put a shower curtain across the width of the wall. Frost the glass

Privacy film but that whole system needs to be waterproof that wood is not.

privacy film. if you shower at night, you might want to stand in the tub and have somebody go outside to tell you how much they can see through the film. (ours has frosted glass and you can still see vague shapes if standing too close.) you could plant a shrub in front of that window for added peace of mind.

I wouldn't freak out too much about that wood trim. how long has it been there? if it looks good now, then somebody did something right. but should probably be inspected on a regular basis.

Vinyl window curtains in a plain color or print. Many choices on amazon and other sites. Example: https://www.amazon.com/Carnation-Home-Fashions-Bathroom-Curtain/dp/B002XQ2LF6

Or buy two identical shower curtains and cut one to fit the window, one to use on the current shower curtain rod.

Great ideas guys, thanks! The wood does show it's wear, but I guess they somewhat knew what they were doing, as I believe that is original from the 60's.

Always love coming here and posting for help, there will be more questions coming soon!