On iOS 16 and later, apps installed outside the App Store only open with Developer Mode turned on. It is a regular switch and gives no access to your data.
Important: the switch appears only after the first attempt to install an app. If you do not see it, tap Install on any app first.
Asked to wait an hour? That is the iOS security delay — see “iPhone asks you to wait 1 hour”. Still no switch after an install attempt — message us.