Rather than having two separate Targets and two separate Schemes, maybe just have one of each.
We can get different Info.plist values by having one Custom iOS Target Property set to a Build Setting, and then have two values for that Build Setting.
One for Debug, one for Release. When you Run the app in an emulator or on a connected device, it will always use the Debug setting (unless you specify otherwise). When you Test, it again uses the Debug setting. But when you send an Archive to TestFlight (or the actual App Store), it uses the Release setting.
See Sarun’s post for more.