Sounds like a problem of the branded Contacts app. Unfortunately, many Contacts apps assume that there can be only local and Google contacts 😕
If you really need this, you could try another Contacts app or a custom ROM like Linage.
Is it possible to keep the synced contacts and calendars on the device after deleting the davdroid account?
perfect would be a dialog which asked for keeping information on the device on account deletion.
No. All contacts and events are deleted by Android when the respective account doesn’t exist anymore. If you delete an account, export the data before.
It might be possible to set the “owner account” of the contacts/events to
null instead of
at.bitfire.davdroid directly, but I don’t know if this will even work and can’t recommend to do so as it would be non-standard usage with undefined results.