Hi All, Got the same issue . Show a fix on youtube. Tryed it and i was stuck in the settings. My Personal Apple ID info was locked. And i good not fix it with the sceentime. So had to restore the Phone. After that just what settings and in just 30 min i was back online. Now Screen time is also working in IOS18

Looks like the update from IOS17 to ISO18 Beta is not working oke. After the update got stuck with the lookup on my personal settings. And Screentime was not working. After a reset en restore with the cloud backup had to setup a few settings. But looks more easy then it used to be. So happy that all is working again. Even the Screentime