I already tried this but it doesn’t work with all shapes.
Let’s say you have 2 Lego parts like this
You can put one on top of the other because there’s 2 holes under those parts with the shape and size of the 2 cylinder on top.
If you put them exactly on top of each others, even with best and most complex simple collision (complex collision doesn’t trigger overlap events) and then check collision in UE, it will detect an overlap even if those 2 parts are just barely touching each other but not really overlapping
If you make a copy of this shape, add it to your rendered mesh, scale this shape down at something like 90% of the scale of your rendered mesh and then use it as your collider, the 2 cylinder on top will be smaller and will fit in not scaled holes but the two holed under those parts will be smaller too.