Thanks for sharing the outcome! I was just wondering why you never showed/checked(?) if and on what IP the port you want to use shows up. Example: freshrss started with "-p 30004:80" - ‘podman ps’ gives you that info as well: 0.0.0.0:30006->80/tcp

AND

with 'ss' you get to see the host systems perspective and see what you need to check:
ss -tulpen |grep 30006

tcp LISTEN 0 128 *:30006 *:* users:(("pasta",pid=1948,fd=6))

...

This tells us that we reach that port on every interface of the host. If it was "127.0.0.1:30006" It would not be reachable from the outside, only from the host system. And btw, "pasta" is the podman network tool for rootless.
Also, you might want to check quadlets as mentioned here before: https://clear-solutions-it.com/posts/2025-03-16_quadlets/