Enable HTTP request with DuckDNS enabled

I set up HA so that I can access it both via https://xxx.duckdns.org (with port forwarding 443 to 8123) and, being in the same LAN, via https://192.168.y.y:8123 (by ignoring the SSL error).
I cannot access to http://192.168.y.y:8123 (no SSL) because HA doesn’t accept HTTP requests.
Can I enable them, since a remote access must use port 443 (so it must be HTTPS)?

My DuckDNS configuration:

  accept_terms: true
  certfile: fullchain.pem
  keyfile: privkey.pem
token: ***
  - xxx.duckdns.org
aliases: []
seconds: 300

My configuration.yaml:

  ssl_certificate: /ssl/fullchain.pem
  ssl_key: /ssl/privkey.pem
  ip_ban_enabled: ...
  login_attempts_threshold: ...

This is an excellent tutorial that I found about how to do it: https://kleypot.com/home-assistant-nginx-unencrypted-local-traffic/

Basically, we use Nginx as a middleware between external requests and HA.