Google Calendar isn't your only option. I use this privacy-first alternative instead

Keeping your schedule organized is important for everyone. You can't remember everything by scribbling it on your hand or jotting it down in a notebook. If you want to stay on top of things, take advantage of the free tools available, like Google Calendar or Proton Calendar.

Source : https://www.pocket-lint.com/proton-calendar-vs-google-calendar/