opacity < depthbasedalpha alpha node and bias should be a single vector (I think... only ever used constant1 on these) alpha is strength of opacity, and bias I think is the strength of the feathering. In the depthbasedalpha node, mess with the value of biasscale, I've normally used around 500. Not sure if you can use this…
if something shows up in the editor (geometry wise) it should show up in the game, if it doesn't, make sure the package that you imported the mesh to is saved so unreal has a package to read the geometry from. and yes, your mesh is WAY too high. most of that detail can be stored in a normal map. it's basically a box with…