use List::Util qw( reduce );

my $highest_rated =
   reduce { $a->{Rating} >= $b->{Rating} ? $a : $b }
   grep $_->{Season} == $seasonnum,
   values %$hdata;

my $banner_path = $highest_rated->{BannerPath};

##</code><code>##

my $highest_rated;
for (values(%$hdata)) {
   next if $_->{Season} != $seasonnum;

   $highest_rated //= $_;

   if ($_->{Rating} > $highest_rated->{Rating}) {
      $highest_rated = $_;
   }
}

my $banner_path = $highest_rated->{BannerPath};