After importing an FBX (via import to level) the result looks fine. After re-importing, things go everywhere. Can I send someone a model to checkout?
You mean, you imported a FBX file, after that you remove the FBX file for any reason (by taking care on removing all the materials it got), and then you again import the same FBX file?..
Why don’t you try on this: Import for first time your FBX file, once you have your mesh, migrate it (by right clicking your content browser) and get the file in another UE project. Everytime you need again the mesh, you just migrate from the another project your mesh again. It should solve the problem.
As a good practice, I suggest to wrap your mesh, with your materials into a an actor. When you migrate the actor, you will have all the dependencies files (images, function materials, meshes, etc) without searching manually.
Just look at this: Migrating Assets in Unreal Engine | Unreal Engine 5.1 Documentation
No I mean i’m using the reimport function in the editor.