Sprite particles lights supports was implemented in QTBUG-90797. Consider extending it with support for light directions, so the brightness of the light depends on sprite texture normals like with normal Quick3D models. This should be doable also just in vertex shader side. Depending on complexity might requre own shaders, so amount of feature levels would grow 6 -> 9. Not sure what the API would be and should there be some intensity properties to control how much same lights affect the particles vs. rest of the scene.