Notice I said sisal "type" meaning look of sisal. While sisal is durable it is very open weave and not always soft. Visit a carpet store and tell them you want the look of sisal and tell them your needs for cleaning etc.

We only had one photo of the stairs and no other info or pics for reference as to furnishings but sisal look runner will blend with almost any style.

I have a wool look sisal under kitchen for years, very durable and cleans well but wool is more expensive.

I agree painting treads black along with railing would be ideal.
Leave risers white.