I mostly use basic (event tracking) calendars for now, but they definitely aren't as flexible as the one presented here in terms of UX. More specifically, I us

I mostly use basic (event tracking) calendars for now, but they definitely aren't as flexible as the one presented here in terms of UX. More specifically, I use my Nextcloud server with WebDAV as the web interface and server, Simple Calendar (with davx5) as a mobile application, and Thunderbird as a desktop one. If you know of more sophisticated ones, feel free to share them :)