@Chazzle
I think what’s happening to my connection only happens on the higher channels, example 153, 157.
iPad drops connection, but appears connected. iPad is just barely connected. Rx/Tx link rate in router drops to 14/13 and is stuck there. All other Apple devices link rates are fine and connected. Only way to fix is turn WiFi off and on. Third time this has happened and only on iPad 10.5 on 11.3 beta. iPhone 7 Plus fine, iPad Air 2 and iPhone 6 Plus on 11.2.6 fine.
When I was connected for a few days and all was well, I was on channel 44. Everything else is the same.