Hi Pascal,
Here is one example – https://www.veeam.com/blog/free-windows-linux-backup-while-you-work-from-home.html?amp.
This is the funtional url but amphtml is https://www.veeam.com/blog/free-windows-linux-backup-while-you-work-from-home.html/amp and Google sees this one.
My desire is to move from ?amp to /amp as the plugin specifies in amphtml tag