Related:
You could create a database of ‘global variables’ and these can be referenced in automation formulas, but in order to use them in formula fields, you would need to make sure that any entities that need to use them are linked to them.
This would imply creating a relation between the database of entities that need them and the global variables database, and populating this relation field with the variables for all entities (either using an auto relation or via an automation I guess).