This appears to be the page to pay attention to for actually doing this. https://help.steampowered.com/en/faqs/view/65B4-2AA3-5F37-4227

It appears support is not yet there, but is intended to be.

Yes. I have had either Gemini or ChatGPT tell me I was wrong. There is a video of a person timing a ~5 second run with ChatGPT and it insisted their run was 10 minutes.

Is this ability useful? Debatable.