DAVx⁵ has been successfully tested with Davis.

Davis is a simple, fully translatable open source admin interface and frontend for sabre/dav based on Symfony 5 and Bootstrap 4, largely inspired by Baïkal.

DAVx⁵ settings

Base URL: https://server.example.com/dav/

User name: your email address or username
Password: your password

Make sure your .well-known paths are set accordingly to use CalDAV and CardDAV in a single account with DAVx⁵.