Google Play Services : Plugin Collision

MacOS, Unity 2021.3.19f1 LTS
Android project, Google Play platform.
GooglePlayGamesPlugin-0.11.01

C++ Compiler Configuration: Debug

The plugin I used to manage the Google Play Services was sending me a few errors because the Google Play Games package was absent.
I went to the github, tried many times to get Unity’s Package Manger to recognize the official .git adress, but it never worked.
After reading the Readme.md and finding the .package in the zipped file’s ‘current-build’ folder (I wish the ZIp were better organized), I installed the GPS material and the errors went away.
I encountered Gradle issues where it was unable to fetch the dependencies. Just because I wasn’t using a custom keystore.
To this day, I still don’t understand why this tool fails to grab publicly available resources just because we are using a debug key.
Is there any good explanation to that?

Next (real) problem. I launch an Android build, but I’m told there is a conflict between these two folders:

Assets/Plugins/Android/GooglePlayGamesManifest.androidlib
Assets/Public/Plugins/Android/GooglePlayGamesManifest.androidlib

The first one in ‘Plugins’ contains one single file, the Project.properties. It sits alongside a whole collection of AAR & JAR files
The other one in ‘Public’ only contains an AndroidManifest.xml file.

I also find that there is a ‘Assets/Public/GooglePlayGames’ folder in ‘Plugins’. It contains material that pertains to the Unity proper: an AssemblyInfo.cs script, then a ‘com.google.play.games’ folder with more stuff inside.

The Google Play material seems a bit all over the place but it’s official: if we look into the package’s content, we see that it does install all sorts of stuff in all these varied places.

So let’s try that build, right?
I get an error.

Found plugins with same names, Assets/Public/Plugins/Android/GooglePlayGamesManifest.androidlib and Assets/Plugins/Android/GooglePlayGamesManifest.androidlib. Delete the one of the duplicate plugins.
UnityEditor.AndroidPluginImporterExtension:CheckFileCollisions (string,string[])
UnityEditorInternal.PluginsHelper:CheckFileCollisions (UnityEditor.BuildTarget,string[]) (at /Users/bokken/build/output/unity/unity/Editor/Mono/Plugins/PluginsHelper.cs:25)
UnityEditor.GenericMenu:CatchMenu (object,string[],int) (at /Users/bokken/build/output/unity/unity/Editor/Mono/GUI/GenericMenu.cs:127)

That’s all.

A test I did was to go to Assets, pick the folder at ‘Assets/Public/Plugins/Android/GooglePlayGamesManifest.androidlib’ and deselect all platforms safe the Editor. So that this folder will be excluded during the Android build. Not sure what I’m doing here but it was worth the try.
I quit Unity, reload it and launch the build.
Failed build.
Rather logically, I’m told that the manifest file cannot be found.

OK, so I decide to do something a little bit differently here as I copy the manifest file to the folder with the same name that’s found in ‘Plugins’ and do a build. It fails too.
It really really wants to find a manifest file in the folder at the bottom of the ‘Public’ root one.

Oh, and of course I deleted the Library folder a couple times. It didn’t solve anything at all.

How do I get out of this mess? Do I have to fall back onto Unity 2020 LTS?

Adding this too.

Build completed with a result of 'Failed' in 84 seconds (83658 ms)
UnityEditor.GenericMenu:CatchMenu (object,string[],int) (at /Users/bokken/build/output/unity/unity/Editor/Mono/GUI/GenericMenu.cs:127)
UnityEditor.BuildPlayerWindow+BuildMethodException: 2 errors
  at UnityEditor.BuildPlayerWindow+DefaultBuildMethods.BuildPlayer (UnityEditor.BuildPlayerOptions options) [0x002ce] in /Users/bokken/build/output/unity/unity/Editor/Mono/BuildPlayerWindowBuildMethods.cs:193
  at UnityEditor.BuildPlayerWindow.CallBuildMethods (System.Boolean askForBuildLocation, UnityEditor.BuildOptions defaultBuildOptions) [0x00080] in /Users/bokken/build/output/unity/unity/Editor/Mono/BuildPlayerWindowBuildMethods.cs:94
UnityEditor.GenericMenu:CatchMenu (object,string[],int) (at /Users/bokken/build/output/unity/unity/Editor/Mono/GUI/GenericMenu.cs:127)