Lock membership content for an additional period. This is handy for memberships that should have access to a members-only post after a certain time has passed depending on their level. E.g. Gold level has immediate access, silver has access after 7 days and bronze after one month the post was published.

period_to_lock_member_only_content_per_membership_level.php

<?php
/**
 * Set a waiting period before unlocking a members-only post that
 * the member's membership level has access to.
 *
 * To set which posts to unlock and their individual period (days)
 * set the post id's as the array key and the period as the
 * value of the array key of the $posts_to_unlock variable.
 *
 * You can add this recipe to your site by creating a custom plugin
 * or using the Code Snippets plugin available for free in the WordPress repository.
 * Read this companion article for step-by-step directions on either method.
 * https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */
function period_to_lock_member_only_content_per_membership_level( $hasaccess, $thepost, $theuser, $post_membership_levels ) {

	/**
	 * Set your unlock schedule per level here. (Level ID => time period)
	 * See https://www.php.net/manual/en/function.strtotime.php
	 */
	// Level ID => Time to wait
	$level_schedule = array(
		1 => '1 Month',
		2 => '14 Days',
		3 => '24 Hours',
		4 => '1 Hour',
		5 => '30 Minutes',
	);

	/**
	 * These levels have access to all restricted posts.
	 * Suggestion: This could be for your premium level(s)
	 *
	 * pmpro_hasMembershipLevel accepts single level id, e.g. pmpro_hasMembershipLevel( 6 ), or
	 * array of level ids, e.g. pmpro_hasMembershipLevel( array( 6, 7 ) )
	 */
	// Set your all access level(s) here
	if ( pmpro_hasMembershipLevel( array( 6, 7 ) ) ) {
		return true;
	}

	// If user is an admin, allow access.
	if ( current_user_can( 'manage_options' ) ) {
		return true;
	}

	// Skip if PMPro says they don't have access.
	if ( ! $hasaccess ) {
		return $hasaccess;
	}

	// Should we lock the post?
	foreach ( $level_schedule as $level_id => $time ) {
		if ( pmpro_hasMembershipLevel( $level_id ) && strtotime( 'now' ) < strtotime( $time, strtotime( $thepost->post_date ) ) ) {
			// Set custom content locked message
			add_filter( 'pmpro_non_member_text_filter', 'swap_locked_member_text' );

			$hasaccess = false;
		}
	}

	return $hasaccess;
}
add_filter( 'pmpro_has_membership_access_filter', 'period_to_lock_member_only_content_per_membership_level', 10, 4 );

function swap_locked_member_text( $s ) {
	$s = 'This content is not available yet.';
	return $s;
}