Maybe the 'simplify' method would work.

use Data::Dumper;
use XML::Twig;

my $file = $ARGV[0] || 'file.xml';

my $twig = XML::Twig->new();

my $config = $twig->parsefile( $file )->simplify(
    # keyattr    => 'key',
    # group_tags => { columns => 'column', },
);

print Dumper( $config );
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