Cannot use multiple locales

I have this piece of code in my configuration:

i18n.defaultLocale = “en_US.UTF-8”;
i18n.extraLocales = [ “all” ];
i18n.supportedLocales = [ “all” ];

I use GNOME DE. I am a volunteer localizer/translator and I want to be able to switch between multiple locales. However, only the language specified in i18n.defaultLocale is installed on my system. The options in i18n.extraLocales and i18n.supportedLocales are listed in the langauge selection menu, but the UI interface still remains in English. Only if I change i18n.defaultLocale I the UI inteface language changes accordingly. But this is not ideal. I want to be able to switch between multiple languages in the settings, without the need of hot reloading.

Here is the link to my config: chore: install all locales · itsbilolbek/nix-config@7592b64 · GitHub

It turns out you cannot do that with GNOME in nixos. GNOME prioritizes i18n.defaultLocale