What walkway? If you plan to use this space as access to the backyard then it could use a walkway.

If there's enough sun, Calamagrostis 'Karl Foerster' would work. Tall and narrow.

You have any zone or sun exposure information that you want to share?

Otherwise I'm posting what I'd do in MY climate.

If you get enough sun for ornamental grass then you get enough sun for daylilies- they're a lot easier to lift and divide when the time comes, plus flowers. I wouldn't do a row of single file 'soldiers,' I'd mix it up with some other easy care low growing perennials with different textures- things like geums or even hosta if you've a hose handy.

Any chance of having trellises built to cover the vast expanses of "wall" you have there? Then clematis or something manageable on them for vertical interest. Or hang something decorative to break it up.

Fatsia, hydrangeas, hostas & vines are good options. If you keep the existing walk you could add steppingstones to carry up to & staining existing walk.

What did u do with the stairwell ?