Once the installer finishes, it locks itself permanently. Visiting /install or any of its sub-pages afterward redirects you into the application instead of re-running setup.
This is enforced on the server, not just hidden from navigation — it checks the application’s real installation record on every request, so the lock can’t be bypassed by guessing a URL or resubmitting an old form.
There is no supported way to re-run the installer
If you genuinely need to start over on the same domain — for example, testing on a throwaway environment — that means restoring a clean database and a fresh .env yourself. There is no in-app “reset” action, by design: it would be a serious risk on a real production site with real customer data.