The question isn't about what you'll do when you're replaced by an LLM, it's what you're doing to future proof your job. There is a difference. The risk to hedge against is the productivity boost brought by LLMs resulting in a drop in the needs for new software engineers. This will put pressure on jobs (simply don't need as many as we used to so we're cutting 15%) AND wages (more engineers looking for fewer jobs with a larger part of their utility being commoditized).

Regardless of how sharp you keep yourself you're still at subject to the macro environment.