Is it possible to integrate this Payment Processor with the API Connector?

Here is all the documentation needed: Autenticación - Wompi API

Here is a screenshot of my attempt:

Everytime I try to make a call I get an error. Please help!

If it has an API then the answer is yes. That call you shared is not what JSON is.

Also, it actually looks like oAuth2 user-agent rather than custom token

Yes, I have the API documentation. I have never done something like this so any tips on how to set up the authentication page would help. I just know that it is supposed to be an OAuth2.0 Client Credential Flow

grant_type = client_credentials
audience = wompi_api
client id = app id
client secret = secret id

dont really know what any of that means

is it user-agent? I have seen other examples of client credentials using the custom token