I’m using a DuckDNS domain with caddy as reverse proxy, but it appears that the domain is defaulting to port 80 no matter how I set up the config. I can’t specify a port number in DuckDNS as far as I can tell.
A domain or DNS in general has nothing to do with ports. DNS is primarily used so that you don’t have to remember IP addresses.
Missed opportunity there, not being able to select all the other available USB-PD voltages. Not every circuit runs on 3.3 or 5 V.