> When AI writes better code than I do, how am I supposed to maintain my motivation and identity?

I'm just going to be honest, this is cope. Your self-doubt is correct here and you should listen to it.

This is like a weaver asking how to maintain their identity in light of machines doing what they could do faster and cheaper. The honest answer is to find something else because at best you're delaying the inevitable.

I've spoken in length in other comments about how AI has taken a lot from my own identity so I understand and genuinely sympathise with how you're feeling, but you need understand what's coming and start planning – especially if you have dependants.

The only good news here is that we'll probably only have to worry about getting by for a decade max.