We already discussed some steps that we might be missing. We might want to store test results in SonarQube. We might want to generate release notes and store them in GitHub. We might need to run performance tests. There are many things we could have done, but we didn't. Those additional steps will differ significantly from one organization to another. Even within a company, one team might have different steps than the other. Guessing which ones you might need would be an exercise in futility. I would have almost certainly guessed wrong.
One step that almost everyone needs is notification of failure. We need to be notified when something goes wrong and fix the issue. However, there are too many destinations where those notifications might need to be sent. Some prefer email, while others opt for chats. In the latter case, it could be Slack...