User Agent Info power-up gives you an ability to add header to your server hits, and you can then access that information on your server container and use it for your reporting.
X-Device-Bot, X-Device-Mobile, X-Device-Os, X-Device-Browser, X-Device-Browser-Version, X-Device-Engine, X-Device-Engine-Version header is added in event data inside your server Google Tag Manager.
1. Server-side GTM with multiple domains
2. How to easily add user agent and geo data to server Google Tag Manager
3. How Chrome’s 3rd party cookies blocking impacts the future of online marketing
In this article, I will describe how to set up a custom subdomain within your Google Tag Manager server container. The main advantage of a custom subdomain inside the Google Tag Manager Server container is that it helps to bypass Intelligent Tracking Preventions, AdBlockers and increases cookie lifetime for users browsing in Safari. Pixels will be loaded from your subdomain and run as the first-party.Edited Jan 17, 2024
Learn about how you can use the User Agent Info and GEO Headers power-ups for improved server-side tagging.