There is already the ability to modify an app's name, localized name, description, and icon but not the option to edit keywords. Please add this option.
A recent example of when I wanted to modify keywords was for the application Microsoft PowerToys. I wanted to include the word Dell in the keyword because we're taking away Dell Display manager and want users searching "Dell" to return PowerToys. I'm going to add them to the description for now, but it doesn't make a lot of sense to put the word Dell in the description.