You're not 100% right in your description.
Open/Type 1 means that, as far as your console can tell, there is "nothing" between it and the internet. Open indicates that your console doesn't even need to worry about UPnP because whatever device is your gateway is already handling it (public IP routing, DMZ, port forwarding, etc)
Moderate/Type 2 means that, as far as your console can tell, it has full access to the Internet, but there IS in fact a gateway between it and the Internet handling UPnP requests. Working properly your console should still connect flawlessly, it just knows and has to work (properly) with the gateway to access the internet.
also as others have pointed out, more than likely the issue exists with your router, not your XBONE. Get a quality router.
just stop. moderate is perfectly fine for every modern game. The issue isn't "moderate". it's that your router is not handling things properly. The problem is your router, not the XBONE.
what routers specifically did you try? I don't suppose you actually tried any high quality ones in the $160-200 range?
FWIW, my poor wifi struggled on an Apple Airport Express which is classified as a "decent but not great" router. Speed issues, not really connectivity issues, but definitely speed and range issues. I upgraded it to the current Airport Extreme (802.11ac one) and I have zero wifi/speed/connectivity issues. This is with tons of game systems, phones, tablets, laptops/desktops, etc.. I think at any given time I have probably 12-15 leases handed out.