MySQL was gone in the morning because the kernel picked it to reclaim memory from Redis. Redis ships configured as a durable datastore, and you are using it as a cache. Setup takes ten minutes; the gotchas are memory limits, shared namespaces and the one enormous key nobody mentions.
You got PageSpeed Insights to 98 and six weeks later Search Console still says the same URLs are failing. The score and the assessment measure different things, and Lighthouse cannot measure INP at all. Here is how to fix Core Web Vitals on WordPress in the order that actually moves the report.
Learn how to debug WordPress like a professional. Discover how to fix common WordPress errors, optimize performance, improve security, troubleshoot plugins, themes, databases, and server issues with this complete step-by-step guide.