Hi Meg, 

I did a bit of reading and most sources recommend the best time to prune such ornamental grasses is early spring to allow for rebounding new growth to appear and revitalize the plant. Short answer, I believe you can prune lightly the most offending parts of the plant now (the parts encroaching on your walkway) or remove clumps closest to the walkway and allow for the plants to spread in the following season to fill in. Here are some good sources I found to read more: 

https://extension.missouri.edu/publications/g6661#Ribbon

https://extension.illinois.edu/blogs/good-growing/2023-06-01-it-too-late-cut-back-ornamental-grasses#:~:text=Cutting%20the%20grass%20late%20in,leaf%20tips%20are%20more%20rounded.

Long story short, I think its a less than ideal time to cut back, but it can be done if you are ok sacrificing some of the aesthetic value on your way to a more manageable bed next season! 

Best, 

Kristin