Are you set on using light sources, or would you be okay with a shader that just creates the shadows without checking for specific light sources? It looks like this might do what you want, but you might need to modify it to work with your exact use case (multiple z levels).
Generally it seems like some kind of shader might be your best option, it seems like the 2d lights are intended for casting lights within a given z level rather than between them. If you want more complex shadows across multiple z levels, you might need to create your own light objects (just a position, color, and intensity) and pass them to a shader that does something similar to the linked example, but modified based on your lights list.
It’s possible there’s a simpler way that someone else could chime in with (I’m pretty new to godot), but as far as I can tell the built in 2d light and shadow systems aren’t designed for different z levels, so you’d need to use something else.
I feel like this pattern of people lying to doctors and doctors adjusting things to account for it really messes with rigorously honest people.
A little while back I was reading how when they ask you how much pain you’re in, with 10 being the most pain imaginable, they pretty routinely have people calmly say “12”. So, if you’re actually using the scale where you’ve probably never experienced more than a 9 and would be sobbing at an 8, so you say 7, they automatically assume you’re in basically no pain because you said less than 10.
Kind of wish we could just speak accurately and take each other literally instead of playing games where we try to figure out exactly what lie to tell to convey the truth, but I guess that’s not how most people are wired.