“tar for Windows” is no longer a good one. The last update of it was in 2003, and the plugins cannot be processed by such an old version of tar. The version embedded in Server 2019 seems a new one that works well but cannot extract as standalone software.
For guys work with old Windows Server versions, please try libarchive(http://libarchive.org/downloads/libarchive-v3.5.1-win64.zip), and set tar="[the extract dir]\\bin\\bastar.exe". That works for me!
Regards,
Xiaosheng
The Hong Kong Polytechnic University