Managed WordPress hosting and a self-managed VPS can both serve a fast site. They differ on which failures land on you. A practical comparison covering visit metering, disallowed plugin policies, silent backup failure, patching debt, and a cost model that survives contact with reality.
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.
Your homepage loads instantly and your dashboard takes eight seconds. That is not a contradiction: wp-admin is the only part of your site that never gets cached. Here is where the time actually goes, in the order worth checking.