It is best to save actor in the scene.
How to use SaveGame to save an actor generated by SpawnActor in a scene and generate it automatically in the next open scene instead of calling SpawnActor again。
Actors are destroyed when the level they are in unloads from the game world.
The level unloads when you change to another level.
you want the actor to reappear in the same place it was when you Saved it, or maybe appear in another level so
ewhere else, but only if it was saved?
Then you will still have to spawn it OR use the loadgame to decide whether to destroy it if it is placed in the level beforehand.
you should read something about serialization/deserialization to understand how save/load usually works.
So, to save some object, for example enemy pawn, you must find it in level, get its class, get all its properties (or at least required/modified properties) and save them to file. Then, on load, you must read that file, spawn actor of that enemy pawn class, and apply all its saved properties.
Or, you should save game only on some safe places, where is nothing seroius to save and load.