Any CalDAV server will do. Radicale is an exception. I also find it too simple/barebones.

I have been running Baïkal for years. Multiple users and devices (iOS, Android, MacOS, Linux, Windows etc) with multiple calendars per user, a decent admin web ui, pretty lightweight, easy to install and configure and zero maintenance.

Or just set up your own exchange server.

Personally I miss a proper calendar that can be used directly in a web browser. Like Google calendar but with the frontend living on my own server.

Scheduling and event management should be done in a client if you ask me.