I'm on unstable channel with Solus Plasma. In Dolphin, when I try to open Google drive, the following error is logged:
kf5.kio.core: couldn't create slave: "klauncher said: Error loading « /usr/lib64/qt5/plugins/kf5/kio/gdrive.so »."
Maybe kio-gdrive (1.2.5-4 on my system) needs to be refreshed to support 19.04?