Apple iPad mini 6 connection to 5 ghz wi-fi problem

Having trouble connecting a mini 6 to the 5ghz Wi-Fi radio. A mini 5, a pixel phone, a Samsung Tab, a Denon receiver, a Bose 500, etc have no problem connecting. Wi-fi is produced by an ASUS ZenWiFi Pro AXE11000 Tri-Band WiFi 6E Mesh System (ET12 2PK). Routers have up to date firmware and the iPad is running OS15.7. I have shut down and restarted the iPad and have reset the network on the iPad. I have rebooted both (main and node) router. This was not a problem a month ago.