How to set all md files front matter draft false default ,in config file or other method?

I want to make all my files private default even if draft not set in file front matter part.

But I found just can use build draft false/true.
use global config.yml frontmater:draft does not work.

That’s not possible globally. But you can set cascading frontmatter per section. Markdown files below will take what is defined in the cascade if they have a specific frontmatter not defined.