Next.js 15 + Tailwind + Storyblok + Vercel. No bloated bundle, pages and requests are cached, static generation pages, not a huge HTML. PageSpeed Insights scores are frustratingly unstable — 90 now, 72 a few hours later. I understand this can be normal due to network variability, but try explaining that to non-technical managers. Has anyone actually built an app that maintains a consistent 90+ score on PageSpeed Insights over time?
If so, how did you achieve that level of stability?