You should use port forwarding instead of triggering.
If you have more than one device that call for the same, or overlapping ranges of ports they require, then Port Forwarding will not be ideal. Also, Port Triggering is considered more secure, as it will close the ports back up after a specific length of time.
UPnP is ideal, as you said, but there are indeed cases where UPnP isn't always consistent. It definitely didn't work properly with my PS3. And with my Nintendo Switch, it's also not consistent. I can run the Network Test and get an A. Run it again and get an A. Then run it again and get a D. I was able to replicate this issue multiple times.
But I'm not sure you guys at DumaOS have ever encountered this, seeing as the latest Nintendo console you have in Device Manager is Wii.
In the case of the Switch, however, DMZ is indeed best, since Nintendo asks for WAYYYY too many ports to be open. But in the case of PlayStation, Xbox, and Steam, it is great to have Port Triggering set up, as UPnP is not always consistent.
I mentioned that the Port Triggering feature is desperately incomplete and less than ideal a couple weeks ago. Instead of saying "you don't need it" or "that's for Netgear to sort out", why not take time to familiarize yourselves with a feature that multiple customers have now asked for? Why not advocate, on our behalf, to Netgear, and encourage them to enhance their Port Triggering interface?
Fraser, you are absolutely awesome, and are very engaged with the community here. NetDuma has built an OS that is really special, and awesome. You should be proud of that. Despite the flaws that the XR500 has (and there are a couple), I am very happy with it, and a large part of that is because of this wonderful OS.
But it is really disheartening when we don't feel that our suggestions will be advocated for, directly to Netgear, on our behalf. I realize that there are aspects that Netgear has control over. But the reality is, this router has your brand on it. You should be pointing out to Netgear when there is room for improvement. And the Port Triggering, and the "ReadyShare", and the VPN..... All of these interfaces are absolutely horrid, and things to be ashamed of.
Can we get a commitment from you, right here, right now, that you will at least bring these things to their attention? That you will champion this router's entire package?