translucency sort priority & depth issue


I’m trying to work with two meshes that are z-fighting, with one being a normal surface and the other being a vertex painted decal. Now I know it’s more efficient to do it via mix materials & avoiding using that way, but the meshes already exist that way, so avoiding it would mean I have to find a way to merge the decal mesh into the base mesh but keeping vertex colors for opacity & keeping UVs.

So despite all the negatives about that approach, I would like to know if there’s a way to fix depth issues with Translucent materials.
I made both materials translucent, set the sort priority of base mesh to 0, and sort priority of decal to 1, so that way it always renders on top and there’s no z-fighting. Problem is, if another instance of that decal appears somewhere behind the wall, it’ll still render it on top of the wall without taking scene depth into consideration.

Here’s a video showcasing my problem -