But why does it pick it up?
In my Qt build I have
FEATURE_sql_sqlite:BOOL=ON

/home/user/kde/qt6usr/include/QtSql/qsqlindex.h
/home/user/kde/qt6usr/plugins/sqldrivers/libqsqlite.so
/home/user/kde/qt6usr/plugins/sqldrivers/libqsqlibase.so

And those files are installed