It seems like you want to capture a 'row' of data at the INSTANCE level, and each row of data is keyed by the NAME of the PROPERTY and the content of the DISPLAY node under it, so I would go with:

my @rules = (
  INSTANCE => sub {
    # .... process properties
    # e.g.
    print Data::Dumper::Dumper($_[1]);
    return;
  },
  PROPERTY => sub { $_[1]{NAME} => $_[1]{DISPLAY} },
  DISPLAY => 'content',
);
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