Still facing an issue with Json multiline

Elastic Stack Logstash
2 
input {
  file {
   path => [ "/path/file.json" ]
   start_position => beginning
   sincedb_path => "/dev/null"
   codec => multiline
      {
            pattern => '^\s*{'
            negate => true
            what => previous
			auto_flush_interval => 1
			multiline_tag => ""
      }
  }            
} 
filter {
    mutate
    {
        gsub => [ 'message',"\s*{\r\n\s*",'{']
        gsub => [ 'message',",\r\n\s*",',']
        gsub => [ 'message',"\r\n\s*},\r",'}']
        gsub => [ 'message',"\r\n\s*}\s*]\r",'}']
    }
	
    if [message] =~ /^\[|\]/ {
      drop {}
    }	 
    else {
        json { source => "message" }
    }
	date { 
		match => ["discovered", "yyyy-MM-dd HH:mm:ss.SSSSSS"]
		#timezone => "Asia/Dubai"
		target=> "discovered"
    }
	
}
output {
   stdout { }
}

Result:

{
       "message" => "{\"post_title\": \"Windemuller\",\"group_name\": \"lorenz\",\"discovered\": \"2020-01-12 00:00:00.000000\"}",
    "post_title" => "Windemuller",
    "@timestamp" => 2023-09-30T18:11:06.538084300Z,
      "@version" => "1",
    "group_name" => "lorenz",
    "discovered" => 2020-01-11T23:00:00.000Z
}
{
       "message" => "{\"post_title\": \"Leaks Company Birch Communications inc.\",\"group_name\": \"ragnarlocker\",\"discovered\": \"2020-06-10 00:00:00.000000\"}",
    "post_title" => "Leaks Company Birch Communications inc.",
    "@timestamp" => 2023-09-30T18:11:06.539095700Z,
      "@version" => "1",
    "group_name" => "ragnarlocker",
    "discovered" => 2020-06-09T22:00:00.000Z
}
{
       "message" => "{\"post_title\": \"Brunner Announce ? Hello World !\",\"group_name\": \"ragnarlocker\",\"discovered\": \"2020-06-11 00:00:00.000000\"}",
    "post_title" => "Brunner Announce ? Hello World !",
    "@timestamp" => 2023-09-30T18:11:06.540077Z,
      "@version" => "1",
    "group_name" => "ragnarlocker",
    "discovered" => 2020-06-10T22:00:00.000Z
}
{
       "message" => "{\"post_title\": \"INC RANSOMWARE...\",\"group_name\": \"donutleaks\",\"discovered\": \"2023-09-30 04:27:49.408003\"}",
    "post_title" => "INC RANSOMWARE...",
    "@timestamp" => 2023-09-30T18:11:08.028026200Z,
      "@version" => "1",
    "group_name" => "donutleaks",
    "discovered" => 2023-09-30T02:27:49.408Z
}