The purpose of a reverse proxy is to shield your web applications and not to change ports. You allow access on port 80 and forward it to your internal IP and port. Most commonly, you use a reverse proxy to forward incoming requests like www.example.com to an internal IP and port and at the same time it is very much recommended to encrypt the traffic using for example Let's Encrypt certificates.

Please make yourself familiar with reverse proxies (https://en.wikipedia.org/wiki/Reverse_proxy) and study the numerous examples available on how to set up a proxy server for Odoo, such as https://linuxize.com/post/configure-odoo-with-nginx-as-a-reverse-proxy/.