I see the check box you're referring to. I'm talking about this.
Will I lose my games/apps or saved changes if I disable/remove the Developer mode from my console?
If you decide to leave the Developer Preview Program, you’ll have to do a factory reset on your Xbox One console. When you do a factory reset, all the content on your console is erased. If that happens, you’ll have to reinstall all your games and apps. As long as you were online when you played your games, your Xbox profile, games achievements, gamerscore, and avatar are saved, and you won't lose them.