Hi @lissacj,
This is a tricky one to answer.
To take a step back, it's generally accepted that as visitors move around the Internet they will receive cookies from the big DSPs (Doubleclick, Criteo, The Trade Desk, etc). Meaning it's rather uncommon for visitors to land on your site without a TTD cookie because they will have been visitoring dozens of other sites that are already setting the cookie. If a visitor hits your site without a TTD cookie it is highly likely becase they have recently cleared cookies.
To get to your question, this is difficult to answer due to the asynchronous nature of Tealium. To get the ID on the first interaction of your site you'd have to tie a callback to the Universal Pixel to listen to the response and then trigger the Cookie Sync Tag. To do this callback would require a special integration, and this is something the support team would have to help build.
Otherwise, you can create a JS Extension with a setTimeout function that listens every say 2000 ms to see if cookie utag_main_ttd_uuid exists and if if not re-trigger the Cookie Sync tag. Once it does exist be sure to clear the interval. This would be the easier option to implement.
I hope you find this useful.
Cheers, -Dan
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