Salesforce mobile app fails to launch after installing iOS 16 on the iPhone 12 and above.
Currently iOS 16 (Beta) version of Apple iOS is not supported by salesforce mobile application. The recommendation would be ensure you have the latest version of iOS that is generally available(15.6).
Salesforce team is aware of this issue and fix would be rollout in coming days when major update of iOS 16 is made available.
As mentioned in doc beta versions aren't supported.
We might not be able to predict or replicate the behavior of beta versions of operating systems, so we support the Salesforce mobile app on generally available (GA) versions of iOS and Android only.