Hello,
You should remove the savefiles.
And on the NULL reference, yes you certainly need to make sure you create the UMG before you call the setup node. Everyone who seems to have the null errors, please make sure you have a player controller(if you don’t have any, just make a new one as every pawn has a player controller anyway, just the engine default if no custom one is made).
We’re going to work on making a clearer remove/adding of character stats that will avoid having to remove the savefile. It’s rather simple to make, however it will only be in in a few weeks. For now just remove the savefile.