That's not really a complicated sort. Here's one way of doing it using ST:

@sorted_array = map {$_ -> [0]}
                sort {$a -> [1] <=> $b -> [1]}
                map {[$_ => (split /$delim/ => $_) [$key]]} @$array_2_
+sort_ref;
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For the non-numeric sort, replace <=> with cmp.

You are mistaken however that ST allows more complex sorting. There's nothing ST can sort that you can't sort with a non-ST method. ST can be more efficient though. However, a GRT often beats an ST when it comes to efficiency.

Abigail