The Microsoft.iOS package is a part of MAUI workload and it's not recommended that you try to downgrade it. The only way is to rollback MAUI workload, you have to create a rollback json file and run the command:
dotnet workload install maui --from-rollback-json XXX.json
For more details, you can refer to a comment about pin the previous version at GitHub.
Note: It's recommended that you update Xcode, as there is a high risk of rejection when publishing your iOS app to the App Store using previous Xcode versions.
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