We're losing user journey tracking when anonymous users switch devices during our sign-up flow. Our typical flow: anonymous user visits homepage on desktop → clicks Sign Up → redirects to Auth0 for registration → user verifies email on mobile (creating a new anonymous user ID) → returns to desktop to complete sign-up and select subscription → receives authID upon conversion. The problem is that the final authID only captures events from the device where conversion occurred, losing all the valuable anonymous user behavior from earlier steps and other devices. We need a solution to stitch together the complete user journey across devices and maintain the connection between pre-conversion anonymous events and post-conversion authenticated user data, especially given our external Auth0 authentication flow that creates tracking gaps.