Entity with 1 property , you can do all what you need from anywhere.
I have accomplished something similar to this with a small entity in the database that has 1 attribute. Then build a microflow that either creates an object of this entity (if it doesn't already exist) or returns the first object of this entity retrieved from the database. This microflow should ensure that only one object of this entity exists in the database. Then I call the microflow in the application wherever I need to use or change the value of the attribute.