GPT can't do full code reviews. GPT is very good at finding improvements, such as making code more functional, bad variable names, etc. In some sense, it's like ESLint or pycodestyle on steroids.

It won't find subtle race conditions, abstraction violations, or deeper issues.

I find it makes code reviews shorter and more productive, so perhaps you'll spend 10% of your time instead of 60%. You won't spend 0% of your time, though.