Angular 12 - Issue with proxy

Question

I am currently struggling with the proxy configuration for my Angular 12 project. Basically, my local application runs on http://localhost:4200, and is calling a local back-end application which runs on http://localhost:8080 as follows:

http://localhost:4200 -> http://localhost:8080/dtm_be_war/api/v1/user

http://localhost:4200 -> http://localhost:8080/dtm_be_war/api/v1/user/login

http://localhost:4200 -> http://localhost:8080/dtm_be_war/api/v1/user/logout

Of course, this forces me to have my BE application running on separate server every time, therefore I was setting up mocked json-server which runs on http://localhost:3000 to call instead. The following is what I would like to obtain:

http://localhost:4200 -> http://localhost:8080/dtm_be_war/api/v1/user -> http://localhost:3000/user

http://localhost:4200 -> http://localhost:8080/dtm_be_war/api/v1/user/login -> http://localhost:3000/user/login

http://localhost:4200 -> http://localhost:8080/dtm_be_war/api/v1/user/logout -> http://localhost:3000/user/logout

I tried configuring a normal proxy.conf.json file by looking at several guides, but it doesn't seem to work. Please find my sample:

{
  "/dtm_be_war/api/*/user": {
    "target": "http://localhost:3000/user",
    "secure": false,
    "logLevel": "debug",
    "changeOrigin": true,
    "pathRewrite": {
      "^/dtm_be_war/api/*/": "/"
    }
  }
}

Command in package.json: "start:mock-admin": "concurrently \"ng serve --proxy-config proxy.conf.json\" \"json-server --watch src/app/core/mock/db-admin.json\ --routes src/app/core/mock/routes.json" "

Basically, I would like to make the json-server independent by the version of the api (i.e. v1), since it would meaningless for it.

I believe my configuration is wrong, although the proxy is captured fine, looking at the logs.

Could you please help me?

Thank you in advance.