Filter the subscription delay option for level ID 2 example.

example-change-sub-delay-filter.php

<?php
/**
 * Filter the subscription delay option for membership level ID 2 to be 1 year later if checking out in October.
 * Change "option_pmpro_subscription_delay_2" to "option_pmpro_subscription_delay_X" for a specific membership level.
 * 
 * @see https://developer.wordpress.org/reference/hooks/option_option/
 *
 * Add this custom code to your site by following this guide - https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */
function my_pmpro_adjust_sub_delay_date( $value, $option ) {
	$todays_date =  new DateTime();

	// Get the current month (1-12)
	$month = (int) $todays_date->format('n');
	
	/**
	 * Check if the month is October or later and update the Subscription Delay to be 1 year later.
	 * This will keep the month and day in tact. Tweak this logic accordingly.
	 */
	if ( $month >= 10 ) {
		// str_replace 'Y1' with the 'Y2'
		$value = str_replace( 'Y1', 'Y2', $value );
	}
	
	return $value;
}
add_filter( 'option_pmpro_subscription_delay_2', 'my_pmpro_adjust_sub_delay_date', 10, 2 );