I tested out calendar sync for appointments, but didn't find the feature useful. Now I can't figure out how to disconnect it. What I tried doing was go into my google account and turn off access for chronofy. That just got me an error email. Go central thinks it is still connected to my google calendar and tries to update it.
I hope you are well. You can manage your calendar settings easily. Most of Calendar's settings are straight-forward, but some are more complicated. This article details all of the settings and provides links to use the more complicated ones.