Fortunately, I brought my EA4500 router from the United States when I flew in. I set this router up in my own room so that my laptop and tablet could have wireless Internet access. To try to improve performance and reliability, I've also assigned my router a static IP through the Dynalink router's control panel and also placed it in DMZ. I would like to set the Dynalink router into a complete bridge mode and utilize just the EA4500 for the entire flat since it's considerably better suited for the job, but the connection is set up with PPPoA while the EA4500 only seems to support PPPoE. I also do not currently have the DSL connection credentials. Right now, the EA4500 is set to just receive its connection via DHCP (which gives it the assigned IP address), although I could easily enough set that to static as well.
Would it be worthwhile to install the EA4500 router and connect that to the network switch as opposed to having the Dynalink there? The EA4500 would obviously still have to be connected to that since that's where the Internet connection is coming through, although it seems like it could handle the network strain a bit more reliably. If I were unable to bridge the connection and just (lazily) kept NAT enabled on the Dynalink, it would still reduce that device's DHCP table to one client instead of close to twenty. It would just have to push Internet-bound data to and from the EA4500 at that point, or at least, that's my thinking (please correct me if I'm wrong!).
I'd love to be able to install a basic modem without any routing functionality whatsoever, but such equipment seems to be surprisingly difficult to find in New Zealand! Everything's a modem/router combo.
Long-term, I'm going to be talking to the landlord about upgrading to Slingshot's VDSL, which is fortunately available in this area at the moment (no UFB, though, sadly). AFAIK, Slingshot would provide a new modem/router and the connection would altogether be massively improved. The network simply feels like it's held together by string and duct tape at this point, haha.