Are you sure about not needing to forward any ports? When I remove my forward of port 443 I can no longer connect. I’m not sure how anything would get past your router without the forward, unless you’re also using Nubu Casa.
8. Port forwarding
On your router, setup port forwarding (look up the documentation for your router if you haven’t done this before).
Forward port 443 (external) to your Home Assistant local IP port 443 in order to access via https.
Also forward port 80 to your local IP port 80 if you want to access via http.
Do enable LAN Local Loopback (or similar) if you have it.
Do not forward port 8123.