Explanation
Microsoft recommends defining active relationships whenever possible. They widen the scope and potential of how your model can be used by report authors, and users working with Q&A.
Refactoring methodology (example): Here's a methodology to refactor a model from a single role-playing dimension-type table, to a design with one table per role.
* Remove any inactive relationships.
* Consider renaming the role-playing dimension-type table to better describe its role. In the example, the Airport table is related to the ArrivalAirport column of the Flight table, so it's renamed as Arrival Airport.
* Create a copy of the role-playing table, providing it with a name that reflects its role. If it's an Import table, we recommend defining a calculated table. If it's a DirectQuery table, you can duplicate the Power Query query.
Only one relationship can be active.
Note: If you query two or more tables at the same time, when the data is loaded, Power BI Desktop attempts to find and create relationships for you. The relationship options Cardinality, Cross filter direction, and Make this relationship active are automatically set.
Reference:
https://docs.microsoft.com/en-us/power-bi/transform-model/desktop-create-and-manage-relationships
https://docs.microsoft.com/en-us/power-bi/guidance/relationships-active-inactive