iPadOS 18.0.1 and iOS 18.0.1 have now rolled out, with fixes for some nasty bugs.
https://www.techradar.com/tablets/ipad/your-m4-ipad-pro-can-now-finally-get-ipados-18
https://www.techradar.com/tablets/ipad/your-m4-ipad-pro-can-now-finally-get-ipados-18