Calendula

Calendula is a modern, open-source calendar app for Android. It works
directly on the system calendar provider, so any source synced to your
device — Nextcloud via DAVx5, Google, local, WebCal subscriptions — shows up
automatically, and changes you make sync back the same way.

Create, edit and delete events, including recurring events with scoped
changes (only this event / this and all following / the whole series) and a
simple repeat picker. Calendula also delivers your event reminders as
notifications — tap one and you're on the event.

Optionally, show your contacts' birthdays, anniversaries and other special
dates in your calendar. You turn this on yourself; contacts are read only on
your device, are never uploaded, and are never changed — Calendula only
mirrors the dates into local calendars you fully control.

The differentiator is the design: real Material 3 Expressive throughout,
with dynamic color, expressive motion, and expressive shapes.

Privacy: zero telemetry, no analytics, no network access — your data never
leaves the device.