There is a new pull request by teldra against master on the void-packages repository

https://github.com/teldra/void-packages sddm-locale
https://github.com/void-linux/void-packages/pull/25037

sddm: source .conf
E.g.: To set a different locale than systems locale.

A patch file from https://github.com/void-linux/void-packages/pull/25037.patch is attached