Following updates to QT and Mozc, the input position does not change
from application to application and is displayed in the top left-hand
corner.
Therefore, change the setting to use classicui instead of WaylandUI
as standard.

Fcitx5 displays a warning message in the Wayland environment because
GTK_IM_MODULE and QT_IM_MODULE are set, but please do not worry about
it and use it as it is. If you want to change the text or background
colour, change the theme to something like plasma in Fcitx5's classicui
settings, and also change the Follow light-dark theme setting in the
system settings to ON.