front end – Frontend/Backend Integration: Wait for a Google Cloud function to run and then return result

I am trying to create a tool that receives a user input on the front end, uses that input to run a Google Cloud function and then returns a link to the output, hosted on Google cloud as well.

How can you give updates that a process is being performed, and update the page when it is finished?

The Vs Frontend-Backend Backend-Backend

I saw this model appear in several teams. They have a server with a REST API and a front-end Web project.

What happens often is that the front-end developer realizes that its requests are blocked by CORS and creates a REST API for the frontend that only sends the requests to the main server. This API finally intercepts some business logic and turns into its own server, managing half of the main responsibility regardless of the real main server.

How can this motive be avoided? It is unacceptable to allocate business logic between two API projects and have to run two APIs to use the front-end interface. Is there an appropriate way to create a "parameterize and forget" proxy of the CORS database for the interface, without creating a dump?