We need the Steps to have the Task resolved regarding: How to publish SharePoint calendar on a public website.
We were only able to enable the anonymous access from the calendar to access and not sure how to publish SharePoint calendar in our website.
Checking on this article, it seems sharing your SharePoint calendar to a public webpage is not recommended and is not made to be publicly accessed. There are workarounds provided, one is depending if the calendar is on SPO or OnPrem, if SPO you have to create a web service with access on returning content. You can't share directly due to not being able to share without logging a user in. If you're using SPO, then you have to make the Sharepoint site accessible by anyone.