So here's the deal...Samsung have released the OneUI 7 Beta Program for eligible devices. So what devices are eligible?
S24 Series devices in supported regions that are purchased directly from Samsung and not a mobile provider (e.g. Vodafone, EE, O2, Carphone Warehouse etc).
You can verify whether your device is attached to a carrier by heading to Settings > About Phone > Software Information > "Service Provider Software Version"
If that section looks like this;
Samsung CSC - Where "EVR" is "EE" in the UK - Other examples include CPW, VOD etc etc.
Then you are not eligible for the beta at this time. The reason for this is that carriers often have their own apps and features on phones that may conflict with the beta versions at this time, so they won't be supported.
What next?
If you have purchased your device directly from Samsung, you should be eligible for the Beta, and you should close and re-open the Members app to see the registration banner. If you're not eligible, you won't see this banner.
Also note that Beta programs do fill up, and until more slots become available, Samsung may halt the registration of new users at any time.