"XML::Simple will default to using a SAX parser if one is available or XML::Parser if SAX is not available."

You probably ended up using the PurePerl SAX parser which is/was buggy when it came to encodings. XML::Parser is by far the fastest existing backend for XML::Simple, according to my benchmarks a year ago.

XML::Simple removes the root by default.

my $tree = 
    {
        table => {}
    
    };
$tree->{table} = 
        $xml->XMLin($fileName, 
            ForceArray => ['map'], KeyAttr => []
        )
    ->{table};
[download]

should be

my $tree = $xml->XMLin($fileName, 
   ForceArray => [qw( map )],
   KeyAttr    => {},
   KeepRoot   => 1,
);
[download]