What is the best methodoly to create relations between documents?

Such as Drupal, I would like to fund the best way to associate a document for exemple a "news" to a topic which is a page.

The site contains several pages "priorities" (as topics) and several related content type as "news", events, publications etc...

Each news, events, publications can be associated to one or more priorities to be displayed in the related priority page.

A common page containing all news, events, publications shows a block per content with informations about related priority(ies)

With Umbraco 7, we can use taxonomy module or use relation features.

But with Umbraco 8, taxonomy module is not available.

For the relations, I can create a new "Relation type", Parent "Document" and Child "Document" with bidirectional direction. But I cannot active this relation for a document type....

How I can associate a document to another with relations in Umbraco 8?

Is it the best way to associate documents ?

I know also that we can add a field "content picker" but it's limited to one document and I don't know concerning the performance if it's great...

Thank you