sorry, I updated only the first post with the correct timings
ack from the command line, takes 15 seconds
this code, simpler than your pseudo code, takes 10 seconds

use 5.014;
use warnings;
use Time::HiRes qw(usleep ualarm gettimeofday tv_interval);

my @array;
my $pattern = '\bsala|che|relazione|di|questo|coso|^qui\$';
open( my $filehandle, "<textMatchInAfile.txt" );
my $time = [gettimeofday];
while (<$filehandle>) {
    if ( $_ =~ /$pattern/ ) {
        push @array;
    }
}
say 'time while' . tv_interval($time);
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