I just now applied the 'Chameleon' option under application styles in kde system settings. When I applied the option the settings window closed. I tried restarting my system but I still can't get access to system-settings.
[francois@francois-pc ~]$ systemsettings5
QQmlEngine::setContextForObject(): Object already has a QQmlContext
qt.qpa.xcb: QXcbConnection: XCB error: 5 (BadAtom), sequence: 622, resource id: 0, major code: 20 (GetProperty), minor code: 0
Segmentation fault (core dumped)