Thats why, i never use widgets, to communicate between each other… i rather prefer to create an actor BP controlling them or better, main player… but widgets and blueprints never save anything, they keep the data during the play in a level, then loose everything, not any BP at all has persistence (watch this: HTF do I? Save Variables between Maps ( UE4 ) - YouTube), if you change from one map to the other, they will lose everything since they have to construct again when you load another map… for that reason, you need to use Game Instances, its the only BP that is alive from the moment you start your game till you quit, it can store variables between maps, characters and widgets cant
This is the hardest in games, storing data, thats why you need to plan better before start the project, in this case each Widget has to store the data inside variables at Game Instances, so when you load the new map, each of those BP that require the data on “event begin play” the first thing they do is get that data from Game Instances and apply, bassicaly before storing anything to main player, first… you need to store this into GameInstances (for changing between levels), then store it to player (for current play)
After you quit, and exit, Game Instances also lose all the data, unless you use SaveGame to store it, from Game Instances, then make GInstances to restore it when you “load” a game, or load it automaticaly on event begin play if it is a graphic, settings data, each time you start the game, this seems complicated, but it is not, after you practice,
the big issue is to find out, wich data you should not save, i just finished my first project and i only save about 5 variables: coins (collectables), current mission, weapons collected, loot, ammo, things like this, because if you try to save everything… its months of work and it can cause lots of bugs… for things like, settings, buttons, i create a default gamesave file, and when the game starts, menu restores settings from savegame.
This tutorial is excellent for understanding this logic between maps: [TUTORIAL] PERSISTENCE in Unreal Engine 4 [Eng] - YouTube
then, making a menu for save/load, delete load, … thats more advanced and you need to understand first the savegame GInstances logic, the hardest part i found was buttons for PC and Controller… omg, that was weeks of work, because each little change has to go to a save, have custom values, restore them to default or save customs, make text to show changes as text and recognize restored data… wow… hard work
The simpler the save, the better.