What happens when you run a packet capture on WAN? Do you see anything coming in on 443/tcp?Another thing to check is verify that it's actually a firewall issue and not an SSL problem. Do a client side packet capture when trying to hit 443/tcp and see if you get any response back.
did you restart OPNsense, too?If nothing arrives at your WAN IF you could be blocked by your ISP. Can you safely rule out this scenario? Hence a packet capture on WAN would be very interesting.Regarding port 80 it is working fine on the whole path to your internal traefik install?
Thanks for the status update.Regarding port 80 (HTTP) vs port 443 (HTTPS) you should(*) see some traffic on port 80 going in and out. Usually a HTTP redirection is sent back to the client that points to HTTPS.(*) Not every browser starts with HTTP but with HTTPS immediately. Hence, you might need to enforce http:// in order to test this.