For Contacts, Group Sharing, AR Emoji Stickers & Smart Switch, you need to go into the app settings, then about app, there tap 3-7 times on the version number or app name.
For Internet Browser, enter internet://debug and then go inside Settings, you'll find the Debug Settings last. Also enter internet://flags to use flags like Google Chrome.
For Game Launcher v6 only, I've opened it using Activity Launcher and the password is "gamehome7.8.1".
