The thing is, the way it internet works here is that we just have an RJ45 jack in the wall we can plug into. There's no ISP router/modem or anything like that - you can just plug a computer directly into the wall jack and it'll get an IP and work. This documentation seems to assume there's an ISP router first, THEN the OPNsense box.

Will this work with our setup too? Let's find out over the coming days!