Honestly, I'd just like web browsers to not complain when you're connecting to an IP on the same subnet by entering https://10.0.0.1/ or similar.

Yes, it's possible that the system is compromised and it's redirecting all traffic to a local proxy and that it's also malicious.

It's still absurd to think that the web browser needs to make the user jump through the same hoops because of that exceptional case, while having the same user experience as if you just connected to https://bankofamerica.com/ and the TLS cert isn't trusted. The program should be smarter than that, even if it's a "local network only" mode.

Certificates protect against man in the middle attacks and those are a thing on local networks.