All the simple tools apps are good and the calendar is quite nice these days. You can sync with google calendar with it but it can be local only if you like. I

All the simple tools apps are good and the calendar is quite nice these days. You can sync with google calendar with it but it can be local only if you like. I sync to my Nextcloud server with Davx5 https://play.google.com/store/apps/dev?id=9070296388022589266 https://play.google.com/store/apps/dev?id=907029638802258926... Also helps they are open source and can be installed via F-droid if needed