Thx for the welcome Jonny,
got it working.
This link helped a lot
For Davx5 on Lineage OS the useraccount must be the user who setup the calender.
Automatic detection didnt work it must be url/tiki-caldav.php .
For evolution on MX Linux it worked as well with url/tiki-caldav.php (read and write). Didnt try yet with different useraccounts. Ill post results of further experiments.