We haven't provided Utility tools for creating/editing Stat/Attributes purely because their workflow won't be as repetitive.
Stats/Attributes are created as UObjects and managed by the Stat Manager component. To create a new Stat/Attribute, head into a relevant directory (e.g, SoulslikeFramework/Data/_Stats/), right-click the Content Browser and search for "Stat/Attribute Object".
Open the newly created asset and adjust the properties in the Config tab to your liking.
Now you will see your newly created Stat/Attribute in-game, automatically added to the UI. Where it is added is determined by the Parent Category property.