Schedule Notifiction

It sounds like you want to use our Intelligent Delivery Option: https://documentation.onesignal.com/docs/intelligent-delivery

You can use the Zapier-OneSignal integration to send the notification when you publish the post using “Last Active” for Intelligent Delivery: https://documentation.onesignal.com/docs/zapier

Or you can add some custom code to the plugin:

In this example you will find how the send notification code looks:
https://documentation.onesignal.com/docs/web-push-wordpress-faq#section-onesignal_send_notification-filter

This is how you set the “Last Active” parameter:

$fields[‘delayed_option’] = “last-active”;

More info on delivery parameters can be found here: https://documentation.onesignal.com/reference#section-delivery