I'd argue you didn't lose the joy of coding, you lost the illusion that coding made you real, that it made you you.
I'm not suggesting that the joy of coding is tied to illusions for everyone, just appears to be more to the story in the case of the author based on his framing.
It is never everything, but it should also never be nothing.
I think the author has been telling himself that he derived joy from the act of creating, but his comments suggest otherwise, he was deriving joy from a false belief of what being a coder meant, about what it would provide him. There's a mismatch between what he believes he's getting out of coding, vs what he's actually getting.
Put another way, reality is reality, there is no right reality, or wrong reality. Perceiving it as right or wrong is just our ego trying to bend reality to match our beliefs.