Replace Default Qt version paths in:
vi /usr/lib/x86_64-linux-gnu/qtchooser/default.conf
or in newer releases:
vi /usr/lib/x86_64-linux-gnu/qt-default/qtchooser/default.conf
/opt/Qt/5.12.0/gcc_64/bin /opt/Qt/5.12.0/gcc_64/lib
