When I created my inventory I ran into the same problem. The solution is to not create the inventory on the player but somewhere else and your player just has access to it. I setup my inventory in the game mode since I can just get game mode in my player and cast to my game mode to grab and store it in a variable. If you do this then when your player is destroyed the inventory still exists and upon spawning your character just make sure that it is set in the player to On begin play get the inventory from the game mode and store it in a variable.