Cache-Control for ads.txt, robots.txt and sitemap.xml files that are generated dynamically

I have some “static files” that I build on the fly, because they are generated dynamically.

ads.txt
robots.txt
sitemap.xml

What is the ideal Cache-Control for those files? PS: My server is behind a CDN.

Can I leave them as private or should I go with no-store?

I guess the result would be the same, because neither will be cached by the CDN and private enforces validation any way.