Try following:

my $rules = [
  [ sub { do_some_test_here } => sub { do_some_action } ],
  [ sub { test2 } => [
    [ sub { sub_test } => sub { action } ],
  ],
];

sub process {
  my ($list, $data) = @_;

  my $retval;
  for my $def (@$list) {
      next unless $def->[0]($data);

      $retval =
        ref $def->[1] eq 'ARRAY'
          ? process ($def->[1], $data)
          : $def->[1]($data) || 1
      ;
      last if $retval;
  }

  $retval;
}

process ($rules, { iptc => $iptc });
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