What should we already be doing to stay relevant?

It is already to late.

Before it was journalists getting replaced by GPT3, then Digital artists, Stable Diffusion and DALL-E, and now developers getting overtaken by ChatGPT, with sites like Stackoverflow being the first to fall.

Like journalists having to learn to code, digital artists learning paint, devs must learn to adapt.

You aren't losing your job short-to-mid term. Long term - it's so hard to predict that it's pointless to give advice so do whatever you like.