Give user default membership level when registering

pmpro-level-register-example.php

<?php

// Adjusted from https://www.paidmembershipspro.com/give-users-a-default-membership-level-at-registration/

//Disables the pmpro redirect to levels page when user tries to register
add_filter("pmpro_login_redirect", "__return_false");

function my_pmpro_default_registration_level($user_id) {

$level = pmpro_getLevel( 2 );

	$custom_level = array(
		'user_id' => $user_id,
		'membership_id' => 2,
		'code_id' => '',
		'initial_payment' => $level->initial_payment,
		'billing_amount' => $level->billing_amount,
		'cycle_number' => $level->cycle_number,
		'cycle_period' => $level->cycle_period,
		'billing_limit' => $level->billing_limit,
		'trial_amount' => $level->trial_amount,
		'trial_limit' => $level->trial_limit,
		'startdate' => "'" . current_time('mysql') . "'",
		'enddate' => date("Y-m-d", strtotime("+" . $level->expiration_number . " " . $level->expiration_period)),
	);
			
	pmpro_changeMembershipLevel($custom_level, $user_id);

}
add_action('user_register', 'my_pmpro_default_registration_level');