is ancient debris due to have processing recipes for milling and crushing?

You could phrase this differently:

[Recipe] Ancient Debri Crushing

There is currently no recipe to turn Ancient debri into Netherite scrap using Create. 

This way you avoid the title that gives no info, and phrase it as an issue!
If the devs do not think this is an issue (i.e. there is not meant to be a recipe) then they will say so but it's better than asking a question, because the issues section is not really a place for questions, it's for issues and problems.