I am not familiar with “launch character” but if it’s a transform that’s available in the details tab of the editor, it should be able to be synced.
Check out
SmoothSync.setSceneComponentToSync() - Used to set the Transform that you want to sync. If none is set up, it will sync the Actor. Must have one SmoothSync for each Transform that you want to sync.
However, your main issue might be that you are trying to set the position on a system that does not own the actor. Smooth Sync syncs your scene components (actors, etc.) from the owner to non-owners or from Server to non-servers when there is no owner. So in the case of the owner to non-owners, you will need to move the object on the owner and then the Transform will be synced to the non-owners.
Let me know how it goes.