LLMs are good at the gist of accuracy, not actual accuracy. They could create new XML files that follow a schema, sure. But they won't even do that correctly 10

LLMs are good at the gist of accuracy, not actual accuracy. They could create new XML files that follow a schema, sure. But they won't even do that correctly 100% of the time, and definitely are not awesome at going the other direction. So just write a parser. It will be no more work, and more correct.