Happy to hear the SampleLauncher works 😉
Does the Qt version from KaOS also allow to manually add packages with the Qt MaintenanceTool?
It is possible to add V-Play to your existing Qt installation, so maybe that works then. See here: Add V-Play to existing Qt installation
This way, you would also get a clean Qt installation including V-Play.
Alternatively you can also try to manually add build-targets in your Qt Creator, that refer to the Qt-version of the separate V-Play installation, which also include the V-Play libraries.