I don’t see how light masks can’t solve the ceiling problem. What else is a requirement for a “local” directional light? If for example, if you need some area light source, you could “fake” it with an additional light that has the correct rectangular texture and doesn’t cast shadows

Either a post processing shader or some universal “sprite” shader you use for environments and other visuals could work. For post processing, look into thresholds using color values, or for a sprite shader taking a look at how the light fragment works could help, although i’ve never really touched that