One thing you might consider is getting with the neighbors for a mutually-satisfactory solution. They might be looking for an idea, too!

Frosted glass might be nice.

frosted glass in the bottom.

I do have a good relationship with the neighbors, just fresh out of ideas. I would gladly approach them, but I feel like I need to present a solution. I thought about using the frosted glass spray, which I hear is also removable, so that if I didn't like it I could. Or use a stencil or painters tape to make a design. But I'm just not very clever!

There are blinds that you can raise from the bottom up - that way you could let light in. Is there room for you to plant some tall shrubs? The frosted glass idea is good, but maybe with a design or pattern to let some natural light in - depending on your taste maybe a geometric or curved pattern?

There are patterned Contact papers that are made to imitate stained glass and frosted glass. In the long run, planting a hedge of shrubs or small trees might work well for both you and your neighbors. You can mock it up with some cardboard nailed to 2 by 4's to see how high it would need to get, or alternatively, how tall you'd need to make a lattice on stilts, as it were.