That header is for the browser: Better Living Through Caching (netlify.com)
Netlify uses the netlify-cdn-cache-control header: Caching | Netlify Docs
You can check the headers in the screenshot you sent:
cache-status: Netlify Durable; hit; fwd=stale
cache-status: Next.js; hit
cache-status: Netlify Edge; fwd=stale
That proves the caching is working as intended.
As I mentioned before, there are no static pages with Next.js 14 
Please refer to the linked thread.
If you want static files, use Next.js in export output.