I did have a few ghosts hanging in the configuration. Deleted all caldavio and caldavpersonal parameters using the console and reloaded the configuration files. I now get logs that CalDAV IO is properly configured (no more warnings).
My calendar items remain undef though.
What’s the exact command to enter into the console to get debug logging on caldavIO and caldavPersonal, I can’t seem to figure it out. I have no error, but nothing downloaded into the cache.