All QT5 apps weren’t themed correctly on my system. I fixed it by installing kvantum-qt5 and setting the environment variable QT_STYLE_OVERRIDE=kvantum which you seem to already have set.
All QT5 apps weren’t themed correctly on my system. I fixed it by installing kvantum-qt5 and setting the environment variable QT_STYLE_OVERRIDE=kvantum which you seem to already have set.