Well long story long 
, I started looking at streamlining my SmartThings set up and the most complex rules I have, are around identifying who is home. You know, not everyone in the household wants to wear an arrival sensor around their necks, so I had to come up with some crazy ways of determining presence (yes, I tried the asuswrt way and some other community based solutions, but none really worked for me) 
In my quest to find a more straight forward way to use wifi as presence, I came across OnHub, which does it rather seamlessly. And that made me (re)evaluate my existing network set up.
And here it is. I run 5 wi-fi networks. My HA hubs and devices are on a FIOS Quantum router set for specific channels, my other devices are on a Asus AC1900 bridged router (set on different channels to avoid interference) and my son’s room is on a AC1200 extender with only the the 5 GHz band enabled. It seems to me that I could have the wifi presence I need and only one wi-fi network, if I go with OnHub. But then I wonder why break it, if it’s been working well for a year…