Another question. For the backend state, I assume we only need either meltano[postgres] or meltano[s3] but not both? If I have remote postgres set-up, then that's all that's needed, s3 is not needed anymore? I saw that when we have both set-up, it still does create a lock file in s3.

Depends on your orchestration setup you can technically use both but I wouldn't, I'd just use one. This is all about how you set your https://docs.meltano.com/concepts/state_backends/ / your https://docs.meltano.com/concepts/project/#system-database