I know it’s not everyone’s favourite but I use Nextcloud to manage family calendars and contacts and to sync between Mac, PC, iOS and Android.

Second this, I’ve been using them for a couple of years and the service is rock solid.

A similar solution but I use https://ntfy.sh/ I have the app on my phone and have it set to alert when jobs ping the service. Mine ping on success but it is possible to ping when the job fails as well.