How to apply themes for kde applications?

[maycne.sonahoz]

@anon89812132

I know in case of Gnome i can use the QGnomePlatform so the /etc/environment has to have QT_QPA_PLATFORMTHEME and QT_STYLE_OVERRIDE commented out, but once using qt5ct or Kvantum, something needs to be set there.

I concur.
From what i recall, QT_QPA_PLATFORMTHERE=qt5ct (at the time of qt5ct, now qt6ct) was set in ~/.profile, and qt5ct was configured to use kvantum. One could also directly use export QT_STYLE_OVERRIDE=kvantum instead in order not to use qt5ct as intermediary. (I now have those commented since i switched to KDE.)