Thanks for the replies, both. Interesting take on the UI that it can only have one "main" network per band and the messaging is... well, truly horrible ergonomics.
However, that doesn't seem to explain the same issue in the Guest Network Pro section - if I can create networks there via the...
P.S. I'm considering swapping it for the later RT-BE92U which apparently has fewer bugs. I bought the 86U for its CPU power for encryption but on a 250Mbps connection the 92U may have enough grunt? We don't have any Wifi6E or 7 devices yet, so the 6G channels would be unused and we'd have fewer...
I just got the RT-BE86U and I couldn't add networks after the initial setup process. The "Add a Network" buttons in the Network section of the firmware didn't work.
In Main Network, it came up with a message saying the rules were at maximum and in Guest Network Pro the button did nothing at...