I used the Home Manager option i18n.inputMethod to setup the input method, and I tested Rime a few minutes before.
The word selection menu is always there, and you don’t even need to invoke it.
The input schema menu can be called by pressing the keys Ctrl`.
Here’s my setup:
{
i18n.inputMethod = {
enabled = "fcitx5";
fcitx5.addons = with pkgs; [
fcitx5-chewing
fcitx5-rime
rime-data
];
};
}
(I’m not sure if it’s proper to place rime-data under fcitx5.addons, but it seems working.)