UPnP is only relevant for software that's already running on your machine locally. People here aren't generally talking about outbound connections and I think you both know that. The practical effect of NAT as commonly encountered in a residential setting is to drop inbound unsolicited connection attempts.

And yes, everyone is aware that you could also do that with a stateful firewall. And no, none of us care about arguments of definition that attempt to frame NAT as technically being a firewall based on how it operates in practice. Being intentionally obtuse by refusing to acknowledge the obvious isn't going to convince anyone.