do any of those actually help with prod risk before merge, or are they mostly focused on the code itself?

They only helped with code issues, performance, etc. You also need smoke test skills to validate live deployment right after it is deployed and then make it automatically roll back for any issues found, or just improve your CI/CD.

I am also trying to schedule make them run as much as real use cases so that runtime bugs happen and are sent to Sentry/bugsink/logs/... Another agent will triage them, create issues, and then continue to push more fixes.