This is a bit late. But the exchange of some personal observations when I came across similar problems.
The build process fails if there is an old plugin that is not updated to work with the @ 7.0.0 platform . At least it concerns me. After installing this incompatible plugin, it will ruin the files on the platform. After that, an attempt to reset the project by removing the plugin will also fail, because during installation the files will be placed in the wrong directories. You will need to remove the cordova-rm platform platform, followed by the wrong plug-in channel and re-add your platform before the build is fixed.
Why android@6.30 and android@6.4.0 can work, because it probably uses the older directory of the platform project directory, where, as it turned out, the top level directory / platform / android is used for the "res" and "libs" folders.
Starting with android@7.0.0 , I noticed that the subdirectory "app" has been added, and your "config.xml" and "res" are expected at '/platform/android/app/src/main/res/xml/config.xml' , not '/ platforms / android / res / xml / config.xml'.
An old plugin may have install / uninstall scripts that copy files to the wrong places.
Only 2 ways to fix this problem is to upgrade the plugin or lower the platform, as Bharat Biswal suggests.
If someone has a more specific answer, that would be great.