New TV 4K "not responding" in Home app

I have a new TV 4K (replacing a 1st generation one). The Home Hub function "is not responsive" as reported in the Home app on iMac, 2nd gen iPhone SE, and iPad. There are two other hubs, HomePod Mini & TV HD, which show up properly as 'connected' or 'standby'.

All devices have latest system software, 17.5.1.

All are on the same Wifi network.

The TV functions from the 4K work fine.

The 4K properly shows up as an accessory in the designated room in the Home app.

Also, the TV remote control panel (accessed from iPhone or iPad control panel) does not connect. It only shows a connection to the TV HD hub.

The new TV 4K setup procedure transferring info from the iPhone went smoothly. I assume that means that Bluetooth is working on the 4K.

Suggestions please.