Depth support via the depth buffer would be amazing, thanks for looking into that!
I see, so only when using vertex shadows, you could have objects blocking light? My only issue with vertex shadows is that they seem to be less fitting for games with a 3/4 perspective whereas sprite shadows look more natural to me in those settings. But I'll look into what you can do with vertex shadows a little more.
Edit: This video by FriendlyCosmonaut shows the type of shadow I'm trying to integrate. Thag's only possible with Sprite Shadows, right?