Relax. Apple's AI is basically GPT-2 duct-taped to a voice model, at best. Even if they tried to collect your data, it couldn't do it reliably. They're so incompetent on this that their AI isn't actually worrying.
Also, the tooling they provided to the model is not good either. The 3rd party AI apps by OpenAI or Anthropic can do much more than the system assistant.