Best practice for CI/CD when building a SwiftUI for for different Firebase projects

Question

I am new to iOS development (historically a full-stack guy) and I'm hoping some of you out there can share with me the best practice for setting up an Xcode project that will support a "dev", and a "prod" Firebase configuration.

I use Firebase as my backend and I have a project for each of the three environments.

Each environment has a GoogleService-Info.plist configuration file which I've renamed to GoogleService-Info-Dev.plist and GoogleService-Info-Prod.plist.

I use Xcode Cloud to build my app and deploy to TestFlight right now.

This is what I think should happen:

For DEV

1. Trigger build when a feature-x branch is merged into to dev
2. Set a value Google-Config-File in the info.plist to GoogleService-Info-Dev.plist
3. Use FirebaseOptions to initialize Firebase with the plist file defined in step 2
4. Deploy app to the internal TestFlight group

For PROD

1. Trigger build when a dev branch is merged into to main
2. Set a value Google-Config-File in the info.plist to GoogleService-Info-Pro.plist
3. Use FirebaseOptions to initialize Firebase with the plist file defined in step 2
4. Deploy app to the external TestFlight group

NOTE I did read this suggested approach but I don't want to have two targets. I would rather have one target and have the configuration set during the CI/CD (Xcode Cloud) process.

NOTE If you are curious how I configure Firebase at runtime based on a config property in the info.plist file here is how I do it ...

init() {
    // Lookup the value of the Google-Config-File from the info.plist
    guard let configFilename = Bundle.main.object(
        forInfoDictionaryKey: "Google-Config-File") as? String
    else { assert(false, "Couldn't find Google-Config-File in info.plist") }
    
    // Load the specified GoogleService-Info file.
    let filePath = Bundle.main.path(forResource: configFilename, ofType: "plist")
    
    // Setup the Firebase options using the GoogleService-Info data
    guard let fileopts = FirebaseOptions(contentsOfFile: filePath!)
    else { assert(false, "Couldn't load \(String(describing: configFilename)).plist") }
    
    
    FirebaseApp.configure(options: fileopts)
}

Am I approaching this the right way? Are there any steps I should change?