For me it's crasy having a mobile OS, that claims to be "a safer, beautiful, free and open source mobile OS" and only offering Google Contacts as data source while the Calendar App offers Nextcloud, Generic CalDAV, OwnCloud and Google Calendars.
It should be one of the mayor goals the implement more data sources to the Contact App and make this contacts available systemwide.
It makes no sense, that multiple apps (e.g. Dekko) are managing contacts for their own.

Greetings

Michael