i was wondering to know why pivot is not aligned to mesh center. Its always set to 0,0,0. It would be good to see the option to reset the pivot base on a simple snap to vertex or mesh center.
You can already do this in the editor. The pivot location will not be saved though.
This also details some of the snapping options.Viewport Controls in Unreal Engine | Unreal Engine 5.1 Documentation
If you need your mesh set to a specific point on your meah permanently you should export your mesh at the 0,0,0 world origin of your modeling application. This is also mentioned in the documentation for creating external content guidelines.