Sort the indices, not the arrays themselves:

my @indices= 0..$#arr_score;

@indices= sort { $arr_score[ $a ] <=> $arr_score[ $b ] } @indices;

for my $i (@indices) {
    print "$arr_thumbnail[ $i ] - $arr_url[ $i ] - $arr_score[ $i ]\n"
+;
};
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Alternatively, restructure your data into hashes, and sort that array.