Hi @Frozenfire, finally I have found a solution that may work for you. The magic property is: “Translucency Sort Priority” located at “Rendering” in actor details. At least it work perfect with my 2D project with translucent textures.
You will not have direct manipulation of sorting but you can tell the engine what you want to render under or over everything.
Be careful if you are working with 3D meshes with opaque or masked material it may not work, this property works only for translucent as I understand. Even if your “overlaying mesh” doesn’t use transparency you could make its material translucent while the alpha channel is opaque then play with the “Translucency Sort Priority”.
Check answer where I found the solution: https://answers.unrealengine.com/questions/143785/2d-25d-with-mix-of-3d-rendering-transparency-issue.html