proxy_pass and proxy_redirect have totally different functions. The proxy_redirect directive is only involved with changing the Location response header in a 3xx status message. See the NGINX proxy_redirect docs for details.
Your rewrite statement does nothing other than prevent further modification of the URI. This line needs to be deleted otherwise it will inhibit proxy_pass from mapping the URI. See below.
The proxy_pass directive can map the URI (e.g. from /v2/platform/general/foo to /foo) by appending a URI value to the proxy_pass value, which works in conjunction with the location value. See this document for details.
For example:
location /v2/platform/general/ {
    ...
    proxy_pass http://another-IP:8080/;
}

You may need to set the Host header only if your upstream server does not respond correctly to the value another-IP:8080.
You may need to add one or more proxy_redirect statements if your upstream server generates 3xx status responses with an incorrect value for the Location header value.