Untypical expose of ports

Long story short and I’m just browsing my options for one quick first aid type fix.

Can Discourse use just ports 80 and 443 from its side (does it mean Discourse uses ports 80/443 of Docker?)?

What i’m meaning is can I do something like this:

expose:
  - "83:80"
  - ”80:someport”

Discourse is a backend for Varnish in another VPS, that’s why I’m using already 83:80 without any issues. But I have a need to offer http-access to Discourse and bypassing Nginx/Varnish frontend.

I could fix my real problems, but as I said: this is just one option as quick first aid.

And if I have to use just ports 80/443 in app.yml I can forget this road.

Edit:
I’am aware any non-standard installation and/or use is not supported help-level. I’m asking if it is possible and yes perhaps some tips showing me to right direction. Or plain no is enough roo :wink:

So, am I actually off topic here and now, and like sysadmin would be more suitable place?