Proxy Solution needed

i need a solution, Im using hassio and installed the duckdns addon, i have port forward 443 > 8123, im able to visit the page https:\mydomain.duckdns.org, and it works,

Currently i have installed Grafana addon and i want to display the page as an iframe, i read that using caddy or a proxy server can help, but i need more clarity as im unsure.

Why over complicate with a reverse proxy over just exposing a different port?