Next.js supports fully static export, so they should have went with that.
I run a dynamic website on nextjs static export - landingpages and docs are fully static, login and user dashboard use REST calls to a non-nextjs backend. Blazing fast, no nodejs or SSR in production.
The static export still keeps a large JS bundle which is mostly unnecessary
Astro blows away next.js for static sites, especially blogs.
Next.js supports fully static export, so they should went with that.
Keeping an unnecessary dependency for legacy reasons is never a good move. Be bold and delete things. Your software will be better for it.