It is a bit odd that you are getting the SaveGame first, and then checking DoesSaveGameExist.
Can you tell which path is running when in doesn’t work (in shipping) ?
It might just be a case of the SaveGame not being available in shipping build - the savegame from the editor will not be packaged with the game, you need to generate a savegame from the shipping build itself.
You need to somehow rule out the cause of the issue - it may either be that the SaveGame is not available/detected in shipping build - or the SaveGame doesn’t contain the correct position - or the spawning system simply doesn’t work. Considering your stuff works in editor I’m leaning toward the former. To confirm that, instead of reading from SaveGame, try hardcoding a location to spawn the player at. If that works, then your spawning system works and the problem is the SaveGame.