They're correct - the 208.67.222.123 and 208.67.220.123 addresses are the anycast addresses which will route requests to the nearest resolvers for you. You can also check with OpenDNS themselves with this link: welcome.opendns.com
Well on my BE96U you have to have MLO turned on in the MLO menu AND have to have the "Front haul" switch for the network settings enabled for clients to use it. Thus, indicates at least with my router model or with the firmware that MLO is primarily being used for mesh backhauls. My comments on having it on in the MLO menu but then not enabling it for front haul was brought forth because it solved a LOT of weird issues I was having with connections. Why that is, honestly, I do not know but I now recommend for anyone with a Wi-Fi 7 router and ASUS to have the feature on even if they are not actively using it. Someone in this forum recommended it to me when I was having all kinds of odd issues and it fixed them. This is why I infer that MLO at least for this firmware is intended to be a mesh backhaul because you must explicitly turn it on for the front haul clients. However, personally, from testing using normal 320Mhz is more stable and mostly faster than MLO because they have not figured out the data scheduler portion so that one connection can be all send, and other all receive. The iteration of MLO we have is no better than a "backup" connection, unfortunally. Most companies are already working on "Wi-Fi 8" because of the sheer mountain of work needed to make MLO work the way it was advertised. There is a hardware component to it as well meaning that anyone who bought current generation MLO capable hardware will not be able to truly use it as advertised because these routers don't have the hardware. Anyways sorry, were getting off topic. My post was meant to help a user in this thread that's having weird issues like I was and admitted to having MLO fully disabled. Here is a decent article on what im speaking about. We only have the basic MLO modes available to us. https://www.rtings.com/router/learn/research/wifi-7-mlo