How do I fetch related fields with the API call? Strapi v4

I have a collection named “blog-articles” that has a many-to-many relation with the collection “blog-categories”.
How do I have the fetch api call populate the relations?

Current api call:

const res = 
   await fetch (

Fetch Result
Collection Content Fields

schema.json for the content type

I believe this is intended behavior in v4—check this section of the docs on Population in REST API.