#!/usr/bin/perl

use strict; # https://perlmonks.org/?node_id=11129741
use warnings;
use List::Util qw( maxstr );

my %hash =
(
  266000003 => {
                 "Network1"      => ["NA"],
                 "Network1  ENV" => ["2021-03-08T13:34:59.000Z"],
               },
  566000003 => {
                 "Network1"      => ["NA", "NA", "NA", "NA", "NA", "NA
+", "NA", "NA", "NA"],
                 "Network1  ENV" => [
                                      "2020-09-09T18:36:50.000Z",
                                      "2020-09-09T18:36:50.000Z",
                                      "2020-09-09T18:36:50.000Z",
                                      "2020-09-09T18:36:50.000Z",
                                      "2020-09-09T18:36:50.000Z",
                                      "2020-09-09T18:36:50.000Z",
                                      "2020-09-09T18:36:50.000Z",
                                      "2020-09-09T18:36:50.000Z",
                                      "2020-09-09T18:36:50.000Z",
                                    ],
                 "NETWORK2"      => [
                                      "2021-03-10T18:15:54.000Z",
                                      "2021-03-10T18:15:54.000Z",
                                      "2021-03-10T18:15:54.000Z",
                                      "2021-03-10T18:15:54.000Z",
                                      "2021-03-10T18:15:54.000Z",
                                      "2021-03-10T18:15:54.000Z",
                                      "2021-03-10T18:15:54.000Z",
                                      "2021-03-10T18:15:54.000Z",
                                      "2021-03-10T18:15:54.000Z",
                                    ],
               },
  900000001 => {
                 NETWORK2 => [
                   "2020-12-17T19:36:21.000Z",
                   "2020-12-17T19:36:21.000Z",
                   "2020-12-17T19:36:21.000Z",
                   "2020-12-17T19:36:21.000Z",
                   "2020-12-17T19:36:21.000Z",
                   "2020-12-17T19:36:21.000Z",
                   "2020-12-17T19:36:21.000Z",
                   "2020-12-17T19:36:21.000Z",
                   "2020-12-17T19:36:21.000Z",
                   "2020-12-17T19:36:21.000Z",
                   "2020-12-17T19:36:21.000Z",
                   "2020-12-17T19:36:21.000Z",
                   "2020-12-17T19:36:21.000Z",
                   "2020-12-17T19:36:21.000Z",
                   "2020-12-17T19:36:21.000Z",
                   "2020-12-17T19:36:21.000Z",
                   "2020-12-17T19:36:21.000Z",
                 ],
               },
);

#use Data::Dump 'dd'; dd \%hash;

my %best;
for my $id (keys %hash)
  {
  for my $net ( keys %{ $hash{$id} } )
    {
    for ( @{ $hash{$id}{$net} } )
      {
      /T/ and $best{$id} = maxstr "$_,$net", ($best{$id} // '');
      }
    }
  }
printf "SSO ID: %s, Mfa Cat : %s , Valid: %s\n", $_, reverse split /,/
+, $best{$_}
  for sort keys %best;
[download]

Outputs:

SSO ID: 266000003, Mfa Cat : Network1  ENV , Valid: 2021-03-08T13:34:5
+9.000Z
SSO ID: 566000003, Mfa Cat : NETWORK2 , Valid: 2021-03-10T18:15:54.000
+Z
SSO ID: 900000001, Mfa Cat : NETWORK2 , Valid: 2020-12-17T19:36:21.000
+Z
[download]