no a good engineer doesn't have to read majority what LLM put out - its not the most efficient.

Actually, I would say trust is an intrinsic part of an engineer's job, because the job is to deliver something that can be trusted to do what it says on the tin.

For software engineering, you're perfectly right that reading the code is one way to build that trust. But the industry has evolved many other methods, and I think those (and new methods based on those) will become more and more important in the future.