how-do-i-even.php

<?php
	/*
	 * Various of other things going on up here. I slimmed down the code for readability,
	 * and focus. $companies is an array of .. companies .. gathered from an external API.
	 */

	$companiesToCreate = collect([]);

	foreach ( $companies as $company )
	{
		$companiesToCreate->push( [...] ); /* Pushing some data from $company here */


		foreach( $company->contacts()->all() as $contact)
		{
			/*
			 * I need to fetch contacts from $company and add that to the createMany below.
			 * Basically the best would be if I could just add it to the above push statement,
			 * with a array-key with the name of the hasMany-relation-method in the class.
			 * But I dont assume thats an option. With the current setup, I'll likely have to
			 * Create each company in the foreach, and append contacts to them in the loop too.
			 * Which is not really optimal, considering some companies might have 50.000 contacts,
			 * and that theres easily 5.000 companies in a single array. Likely more.
			 */
		}
	}

	$this->companies()->createMany( $companiesToCreate->toArray() );

Didn't even reply to the comment. Went back to this (at random) and remembered that your solution fixed this. Thanks so much!! 👍