Hello there bronagh64,
We understand your Google Calendar has stopped syncing after you deleted and added back the same account on your iPhone. Is that right? If so, let's take a closer look as we do our best to provide some additional insight.
To get started, have you already tested syncing both ways? For example, add an event on one of your Macs to see if it syncs to the Google website, and then see if it syncs to your iPhone? Then do the same the other way from your iPhone, to the Google website, and then see if it shows up on your Macs.
In the meantime, you'll also want to make sure you have the Google calendar syncing enabled under Settings > Calendar > Accounts, and also ensure that this is set as your Default Calendar.
While these steps typically cover iCloud account sync issues, most of the steps can also help with other accounts as welI: If your iCloud Contacts, Calendars, or Reminders won’t sync
We hope this helps!
Take care.