New comment by b1scu1t on void-packages repository

https://github.com/void-linux/void-packages/issues/25252#issuecomment-714626790

Comment:
You are correct. It seems that you must manually specify the database back-end in `~/.config/akonadi/akonadiserverrc`.
It's set to 'Q**MYSQL**'  by default.
Check here for more info: https://wiki.archlinux.org/index.php/KDE#SQLite

Akonadi also supports PostgreSQL, apparently.