How do I completely remove Apple Calendar and stop double alerts on iPhone?

Do you have Screen Time Restrictions set that prevents deleting the Calendar app? It is one of the many installed apps that can be removed completely from your phone, not just moved to the App Library. If you have Screen Time restrictions preventing App Deletions, then you only get the option to Remove it from your Screen. This can be checked at Settings > Screen Time > Content & Privacy Restrictions > iTunes & App Store Purchases > Deleting App, and it should be set to Allow.

Remove or delete apps from iPhone - Apple Support

Also quit syncing any of your Accounts at Settings > Apps > Calendar > Accounts.

2lanerider wrote:

How do I completely remove the apple calendar? Don’t use anything but Google calendar. But I keep getting a notification that my CalDAV password is incorrect. Never heard of CalDAV until that error occurred. I also get double alerts - one from my Google calendar (expected) then immediately after I get another one that looks like it’s coming from my Apple calendar. I have gone through the apple calendar settings and turned off everything I can find, but it keeps happening. Anything I can do short of getting rid of my Apple phone?

If you're only using gmail to sync your calendar, then the issue is coming from google and not Apple.

Yes that is strange, are you able to delete any other apps? I have both options for the Calendar app, to Delete it and also remove it from the Home Screen, where it will reside in the App Library/