Can't Delete a Subscribed Calendar

I have the same issue. iOS 16. There's no Unsubscribe option or Delete button. It's a holiday calendar that I've had for several years.

Apple support's article:

Set up multiple calendars on iPhone – Apple Support

says:

"Unsubscribe from a calendar

You can unsubscribe from a calendar you’re subscribed to. When you unsubscribe, you can also report the calendar as junk.

1. 1. Tap Calendars at the bottom of the screen.
   2. Tap  next to the calendar you want to unsubscribe from.
   3. Tap Unsubscribe, then Tap Unsubscribe or Unsubscribe and Report Junk.
   4. Note: When you tap Unsubscribe and Report Junk, the calendar is reported to Apple as a suspected junk subscription".

So looks like you should have an unsubscibe button ... which you press twice. after the red "i"

If that's not happening

Wondering if this Apple Support article can help to delete that subscribed calendar:

Delete spam calendars and events on iPhone - Apple Support

All the best :-)