When running windeployqt on an application using Qt Virtual Keyboard the qtvirtualkeyboardplugin (from $$[QT_INSTALL_PLUGINS]/platforminputcontexts) is included correctly, but qtvirtualkeyboardstylesplugin (from $$[QT_INSTALL_QML]/QtQuick/Enterprise/VirtualKeyboard/Styles) is not.

It seems that the qtvirtualkeyboardstylesplugin in included only if QML import scanner finds virtual keyboard module. In other words importing QtQuick.Enterprise.VirtualKeyboard module in the application can be used as a workaround.