I don't see "device id" on that page, just "Identifiers"

I don't believe that iOS apps get a stable device ID. It may be that Google is generating one, and it can be shared across Google apps. But I'm pretty sure there is no global device ID that's common across all apps.

The original point stands that if you use recaptcha and you're signed in to a Google account on the device and you then use another Google app and you've done some form of identity verification with Google, then Google could link identity to recaptcha.

But I think the claim was over-broad about device ID.