Introduction
OAuth endpoints are a little different and work with different domains and tokens. OAuth endpoints along with OAuth Authorization are basically used for the Tool Plugins and Custom Sidebar Apps to interact with Management API. It is a multi step process to get the token and send a request using it.
You can read more about the OAuth 2.0 Authorization flow here.
The token for making requests from inside the custom plugins is retrieved following the OAuth flow linked above. It is not the same as the management API token.
Using the OAuth token you can use many other endpoints as well. You can take a look at the Management API Reference here for the same.
One important thing to note is that the domains for making these requests to oauth endpoints are different from the general Management API domain.
Here is a list of domains for the different regions -
https://api.storyblok.com/