Thanks very much Lubuntu team for creating Lubuntu.
Lubuntu 21.04 now use File Archiver instead Ark in 20.04 or was renamed to File Archiver.
Trying to extract a tar.bz2 file the files not are correctly extracted and not are created sub folders.
Test file in the link below
or access the download page
That same downloaded file is extracted correctly if using Peazip.
a problem with File Archiver ?