Siri Ai

Not unusual. Many users who downloaded iOS 27 at first were able to join immediately, then it slipped to hours. Since then there have been significant delays, just like when Apple Intelligence was released. There was also a waitlist when that was released and later users who joined the waitlist ended up waiting several days as the rollout was being managed to gauge server load.

Also I suspect you are seeing in Settings that the Siri & Search Optimization is still being performed in the background. As it says there, that will finish quicker when your device is not being used, plugged into power, and connected to WiFi. Leave it plugged in all night, every night to give your phone the best opportunity to finish those background processes so you are ready to take full advantage of Siri AI when you leave the wait list.

No one here knows what the criteria are for prioritizing or not prioritizing users.

However, I imagine it's based largely on bandwidth and server capacity serving the particular regions that users on the waitlist are in.

Be patient.

I downloaded OS Golden Gate 27 to my iMac and I am also on the waiting list. It is frustrating that many YouTube videos explain Siri AI feature capabilities that we are waiting to receive. Do the iPhone users go to the head of the queue?