Hey @corel_kri001,
So then what you want is an interface. For example, an interface will let you call a function that will send required information to your main actor / blueprint, no matter what the secondary actor that is interacting is. Some examples include interacting with objects, opening doors, collecting powerups, and sending xp / money to characters for killing an enemy or quest rewards.
You will not need to create “global variables” in order to accomplish this and will be able to send whatever type of data you need based on what you are doing.
Here are some more non-Epic affiliated tutorials that demonstrates the versatility you are asking for:
We need direct specifics on why this will not work for you if this will not work with your setup, however, this will allow you to communicate between your blueprints with as little extra variables and let you contain your necessary data in your respective blueprints without needing to add any bloat.