the sheer amount of complexity involved in just having a calendar that works with other people

nextcloud -> ah yes the go fuck yourself experience, what is a VPS server, php-fpm, docker container was broken as shit and it turns out i used to run ours on one i made myself
everything else -> idk man put radicle somewhere and pray

to be fair radicle IS mostly turn key and walk away, but it only does the caldav on the backend and you still need other stuff