HomeKit stopped working - but works for 1 minute after restarting iPhone?

Hi I have been using the Home app for over a year with no problems at all. It’s been perfect. Then, just over a week ago it stopped working. Nothing changed in our system. It just stopped.

As it stands now:

All accessories are “not responding”

Even my hubs- HomePods (I have 3) show as “not responding” - under settings, even though I can hit play in the home app and they play music(?) so they are clearly connected.

I have Hue lights. And they worked fine until this.

I can control all my lights in the Hue app no problem.

I have tried all the basic fixes:

• quit the home app
• verified that devices are on the same network
• restarted our phones (repeatedly)
• power cycled the accessories
• Powered down every single part of our network, router, Ethernet hub, WiFi access points modem and all accessories, waited for 10 minutes then powered them all back up again starting with the modem.

The only thing I have not yet done is reset all devices and start all over. If that’s the “fix” then I’m basically back to debating this and competing systems.

One weird condition:

when I restart my iPhone everything works for about 60 seconds. I can control the lighting everything seems to work. And then poof - not responding. Which makes me think this is not some problem with the accessories. Maybe even the network. It feels like a software problem. As if this came with an iOS update or something. But it just feels like that.

what’s going on? Why does it work for a minute - then stop - just from restarting the phone?

And why does the home app say my hubs are not responding under “settings” when they show as “paused” on the Home Screen?