iCloud Calendar events not syncing across devices and web

Hello,

I’ve been using the calendar app with iCloud (paying user and used only 25% of my storage plan of 2TB) for many years with primarily iCloud backed calendars (but as well as external calendars like Google Calendar). Recently for 9 days now my iCloud calendar events have stopped getting synced to my other iDevices. On visiting iCloud.com the calendar there also doesn’t show any events I created or modified for the past 9 days now, and furthermore when I create an event on iCloud.com calendar for any of the iCloud calendar that it shows an error with a “report to Apple” (which I did) and the event does not save.

I have tried contacting apple support, but nothing is there besides the AI chatbot.

Thank you.