I'd probably do it something like this. (Untested code...)

use strict;
use warnings;
use aliased 'Path::Class::Rule';
use Path::Class qw( dir file );

my $files = Rule->new->file->name(qr{\.txt$})->iter;
while ( my $file = $files->() )
{
    (my $newfile = $file) =~ s/\.txt$/_new.txt/;
    $newfile = file($newfile);
    
    print "$file  ->  $newfile\n";
    
    $newfile->spew(
        map {
            s/^(.*?)\.(.*?)\ (.*?)\.(.*?)\ (.*?)$/$1\t$2\t$4\t$5/; $_
        } $file->slurp;
    );
}
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