Apple has released iOS and iPadOS 14.0.1 to the public with a fix for the default apps bug and other issues.
iOS 14.0.1 fixes an issue where a user’s default email and browser apps would reset to Mail and Safari after restarting your device. After setting a default app, it will no longer revert to Apple’s equivalent.
The update resolves a problem with the Apple News widget not displaying images. It also fixes connectivity bugs.
iOS 14.0.1 can be installed now in Settings > General > Software Update.