Try something like

my $regexp = Regexp::Assemble->new(
  flags => 'i', track => 1
)->add(@patterns);

if( $regexp->match($string) ) {
    print "$string was matched by pattern ", $regexp->matched, "\n";
}
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This doesn't use $&, and also performs only a single match, no looping required. You could use the matched pattern as a key into a hash, and set up a dispatch table.