Here's a solution to the first part of what I guess your problem may be. (Please see Short, Self-Contained, Correct Example and How do I post a question effectively? and I know what I mean. Why don't you?)

Win8 Strawberry 5.8.9.5 (32)  Mon 09/20/2021 13:56:49
C:\@Work\Perl\monks
>perl -Mstrict -Mwarnings

use Data::Dumper;

my $accounts = [
    {
           'date' => '1980-03-05',
           'year' => '2019',
           'acc' => '44443',
         },
    {
           'date' => '1999-06-19',
           'year' => '2017',
           'acc' => '54321',
         },
    {
           'date' => '1999-09-19',
           'year' => '2099',
           'acc' => '12345',
         },
    ];

my $filtered_accounts = [ grep { $_->{'acc'} ne '54321' } @$accounts ]
+;

print Dumper $filtered_accounts;

^Z
$VAR1 = [
          {
            'date' => '1980-03-05',
            'acc' => '44443',
            'year' => '2019'
          },
          {
            'date' => '1999-09-19',
            'acc' => '12345',
            'year' => '2099'
          }
        ];
[download]

Update: I don't really understand the rest of the OPed problem.