Factory seeding large amount of records

I'm currently testing our database structure and select queries with more realistic record amounts. I'm very new to Laravel, so I might not do things as optimal as possible.

Situation We have 1 table (candidates) that will contain 15K records easily. Each of these records will have 2 pivot tables connected to other (smaller) tables (connectors and skills). In total about 795K records will be created to make the correct links and data realistic.

Problem I've run into a problem when trying to create the 15K records with an ->each(function()) on each creation. I run into memory problems, even though I'm saving the pivot table records for each user before moving on to the next ->each().

What's the flow for seeding? Does the Laravel Seeder save each user first and then loop through them all and execute what's in the anon-function? Or does the Laravel Seeder save a user and then execute the anon-function before moving on to the next user?

I've added in a progressbar for testing purposes (and up it 1 step whenever I've created a test record for one of the pivot tables) and it's not moving once I start the seeder. For other table seeders it finishes too fast to follow so I'm confused why it's not counting as soon as I start the command.

Code

public function run()
    {
      $output = new Symfony\Component\Console\Output\ConsoleOutput();
      $output->writeln("----------------> Candidates <----------------");
      $this->command->getOutput()->progressStart(795000);
      
      factory(App\Candidate::class, 15000)->create()->each(function ($candidate) {
        $faker = Faker::create();
        
        //Init insert bulk
        $connectorBulk = array();
        $skillBulk = array();
        
        for ($i = 0; $i < 3; $i++) {          
          $array = [
            'candidate_id' => $candidate->id,
            'connector_id' => $connectorUnique, //I get this outside of the anon-function. This has been tested and works.
            'created_at' => Carbon\Carbon::now(),
            'updated_at' => Carbon\Carbon::now(),
          ];
          $connectorBulk[] = $array;
          $this->command->getOutput()->progressAdvance();
        }
          DB::table('candidate_connector')->insert($connectorBulk);
        
        for ($i = 0; $i < 50; $i++) {
          //Uniques
          $skillUnique = $this->unique(App\Skill::inRandomOrder(), $skillArray, 'Skill');
          
          $array = [
            'candidate_id' => $candidate->id,
            'skill_id' => $skillUnique, //I get this outside of the anon-function. This has been tested and works.
            'type_value_id' => App\TypeValue::all()->random()->id,
            'related_id' => $faker->numberBetween(1, 15),
            'created_at' => Carbon\Carbon::now(),
            'updated_at' => Carbon\Carbon::now(),
          ];
          $skillBulk[] = $array;
          $this->command->getOutput()->progressAdvance();
        }
          DB::table('candidate_skill')->insert($skillBulk);
      });
      $this->command->getOutput()->progressFinish();
    }

If I run a smaller number (tested up to 12.5K) of Candidates to create it takes a while for the progressbar to start counting up, but it does eventually, which leads me to think that it creates the Candidates before looping through them. Seems like a memory hog to me if you want to seed large amounts of data.

Please correct my assumptions if they're wrong. Also, if there are easier ways to populate pivot tables let me know. I have a few of them and couldn't find a decent way other than DB::table()->insert().