Hello kmk2991,
We noticed you’d viewed another thread with the same issue. In that one, restarting in safe mode and testing in a new user account was recommended. Were you able to perform those steps?
If not, here’s the links again:
How to use safe mode on your Mac - Apple Support
Add a user or group on Mac - Apple Support
With safe mode we want you to be aware that restarting in safe mode may take a bit longer than usual since it prevents some software from loading and does a check of your startup disk. You may also see some graphic anomalies on your screen as well. Once you’re done testing, restart normally to exit. If the issue didn’t occur while in safe mode, see if it happens after a normal restart.
With a new user account, you’ll need to log out of your own account, then into the new account. Set up the Calendar as you have it set up in your own account and test.
Please let us know the results when you're able.
All the best.