It does not look like NAT loopback will be an option for me due to router/ISP.

Thanks for the ping suggestion. Copied from another comment of mine:

When I ping docmost.example.com, looks like Adguard is correctly catching it and routing it to an internal IP 192.168.1.80, which is exactly what I’ve told it to do. I tried to ping anothersub.example.com as well, and it was pinging my duckdns address and timing out. So when I ping, it looks like the packets get through but when I try to access it from a browser, it times out?

puu.sh/Ks252/fa872908d9.png

When I try to connect to docmost.example.com, I do not see anything come up on my proxy-host-##_access.log, proxy-host-##_error.log, or error.log. Just nothing at all. When I access from outside the network, entries in the log show up as expected from the IP I access it from (in this case, my phone off WIFI).

I pinged 192.168.1.85 from within my nginx container and looks like it communicated just fine. puu.sh/Ks29s/367c0b6144.png