This is how you would do custom collisions just like normal, just put them inside the collision collection.
https://epicgames.github.io/BlenderTools/send2ue/collections.html#custom-collision-meshes
LODs Just need to be named correctly ‘_LOD#’ and the LOD option needs to be on
https://epicgames.github.io/BlenderTools/send2ue/preferences/import.html#lods