C8 hub shows devices but everything quit working

I have a C8 hub with a mix of mostly Honeywell, GE switches and dimmers, and then a few sundry Z-wave devices. I was traveling and returned home to none of the automations working. I have no idea what went wrong but nothing on the device list will respond to a manually initiated on/off command, all automations are non-functional, and the Z-Wave Device Topology map is just wacked!

The hub is a C8, as mentioned, running 2.3.9.184.

The "Last Activity" date on the devices page show all devices at least a week old, some more than a week, others much older than that.

Suggestions for where to go from here to get back to a functioning state of Hubitat automation?

Regards, Bryan

The #1 thing we advise when the entire radio jams, is to do a physical power cycle.

Settings: Shutdown. When the device is shut, unplug it for 10 seconds or so and power it back up.

The Radios stay powered 100% of the time and the only way to reset them is via a complete power cycle.

Welcome, please see this helpful post:

I think you got things heading in the right direction. Thank you.

I still have a bunch of devices with "Last Activity" date that is > week old with several being a couple months old. How should I proceed with all of these devices? Leave them for now, remove/exclude and re-add? Suggestions? Again, thank you.

Regards, Bryan

Click refresh, or physically activate the devices.

The last Activity will only update if the hub hears from them.

If your z-wave radio was down for a week it may take 24-48 hours for all the devices to fully recover. They may need to rediscover the routes to the hub, which cannot happen until the closer devices are working first.

You should not need to exclude anything.

The Z-Wave region is set correctly for my area, US-LR - 908.4 Mhz, 916 Mhz.

Well, after close to 48 hours it seems things haven't improved beyond the Z-Wave graph appearing to have recovered.
No automations were running after waiting for the environment stabilize so I checked on the device page and found that while I can see them listed, they are no longer responding to simple on/off commands. Many of these devices were working but they are not working any longer. I am reaching out again for suggestions.
Regards, Bryan

Shut down hub and unplug for 30 seconds. Once it is back up focus on one device. Pick something closer to the hub. On zwave details run a repair on it. Try activating the device physically a few times then from the hub a few times. Results?