What is your plan if AI starts replacing engineering jobs?

You can look at this two ways:

1. Feed your family. What will it take? An Amish-like techno-secluded community? Or stay ahead of the pack and look at where the jobs are moving to? (hint: it will still be computers)

2. Who needs to input into the GPT machine? At what point does typing the definition of the requirements out-weigh typing actual code? Will GPT ever be trustworthy enough to not have QA on its outputs?

Or maybe you are referring to the far future, to the point that AI + quantum computing + energy storage + automation becomes so self-contained, that humans are reduced to a life of constant entertainment generation for one another?

I'll move up to thinking in terms of the higher level of abstraction one uses to manage the new layer of automation, just as I've been doing throughout my career. The details of the tools change over time, but the fundamental nature of the process stays largely the same.

Do the job that controls the AI?

Be the AI's manager.