The lifetime of first-party cookies for Safari is since ITP 2.1 only 7 days. There was a workaround for this limitation that could place cookies from a sub-domain with the use of for example Google Tag Manager Server Side.
Jos IJntema wrote a very nice Dutch article about some changes in this workaround.
He explained that with the new Safari version 17, your Server Side tracking needs to have a first-party IP.
Your server has a First-Pary IP when it has a 50% of the same IP address from the server of the website.
For the Dutch article have a look at: https://www.linkedin.com/pulse/let-op-ga4-statistieken-worden-opnieuw-beperkt-vanaf-safari-ijntema%3FtrackingId=1IZygXUwSIObOZeH95H9qg%253D%253D/?trackingId=1IZygXUwSIObOZeH95H9qg%3D%3D
