I really don't know if this is specific to the package or to xcframework or to the setup. In my case I just:
- open VS 2022
- create a Xamarin iOS empty project
- add the Google Mobile Ads 8.13.0.1 Nuget package through the VS NuGet package manager ( this is the package https://www.nuget.org/packages/Xamarin.Google.iOS.MobileAds/)
- build
- get this error:
C:\Users\Admin\AppData\Local\XamarinBuildDownloadCache\GAppM-8.9.1\GoogleAppMeasurement-8.9.1\Frameworks\GoogleAppMeasurement.xcframework has an incorrect or unknown format and cannot be processed.
I've been using google ads in iOS projects for 10 years, updates tend to screw everything up, but it's usually fixable, this time I'm completely stuck.
I tried filing a bug report (https://developercommunity.visualstudio.com/t/GoogleAppMeasurementxcframework-has-an/10153891?entry=problem) and an issue on github (https://github.com/xamarin/GoogleApisForiOSComponents/issues/573) , but experience tells me it's useless...
[EDIT] The project is here: http://www.andreasabbatini.org/Files/AdmobTest.zip