Nginx Expert Support Required

I have Nginx setup on a server for a domain and all works well. I'm trying to use it as a reverse proxy to redirect requests to a different subdomain and returns the response from that subdomain to the user's browser, without the user ever seeing the subdomain. The subdomain is a service hosted on cloudflare. Been banging my head for a while but can't get it to work.

In a nutshell I need the following:

Https://example.com/test/file.ext

Reverse proxied to

Https://subdomain.example.com/test/file.ext

tried a few combinations such as the below, to no avail.

server {
listen 443 ssl;
server_name example.com;

ssl_certificate /path/to/ssl_cert.crt;
ssl_trusted_certificate /path/to/ca_bundle.crt;
ssl_certificate_key /path/to/ssl_key.key;

location / {
proxy_pass https://subdomain.example.com;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
}
}


Need chat support to help me solve this issue.