For anyone who's experienced the lengthy post-update indexing process when trialing the beta version of iOS 27, macOS 27 Golden Gate, iPadOS 27, or visionOS 27: Apple has published a Spotlight support document that explains what's going on.

Apple says indexing can take hours or even days depending on how much data you have stored. It completes more quickly when your device is not in use, and when it is connected to power and the internet. Apple also confirms that the index is stored locally, remains private, and is not shared with Apple or any of your other dev

Macworld