I have a new C8 Hub that I purchased a few months ago to be used to migrate my C7 Hub currently running for the past few years with hundreds of devices and routines.
I did a quick setup of my C8 hub just to have it running on my network with no devices and no apps connected via RJ45 to my router running the latest and greatest Hubitat version.
The C8 hub will be operating fine for a few days and suddenly, one morning he hub is no longer accessible and it will be disconnected and no longer visible from the router. The green led visible and steady. The hub is not accessible from the the IP or Mac Address as it seems to be frozen.
I tried to do a Network Reset by holding the small button beneath but the hub is not responding, the green led won't blink it will remain steady,
I did a backup and restore of the database which did not help.
I added 2 devices to test the C8 hub to see if this could help but same result after a few days. No matter what I try, so far, I am getting the same result, it will freeze after a few days.
Again I have a C7 hub on the same network that has been running without a single issue for the past year, I keep both hub to the latest version as soon as I see a new one available.
I read all comments from this community about unresponsive hub as it seems to be happening to a few members and tried a lot of member recommandations with no luck so far, the hub still hang after a few days.
If anyone could shed some lights on this issue would be very welcome.
I was / is having the same problem ..
I tried everything you listed. and many other things.
I finally tried a * soft reset * from the Hubitat Diagnostic Tool
Kind of a nuclear option 
But seems to have helped me.
I did this on : 1/02/2024 and the HB has stayed online since then 
Just make sure you do a backup because if you try this you will have to restore of the database
Anyway give it a try ? see if it helps .. It did me.
I will give it a try now and get back with the results.
Thanks your reply!
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On Jan 6, 2024, I did the Soft Reset and restored a database backup. Everything was running fine for 3 days and this morning I get 'The site cannot be reached' on the browser. The hub is unresponsive.
Soft Reset - Checked!
If you have another suggestions, I will give it a try for sure!
Noting that the LED is remaining green - Do your automations also stop running or is it just accessing the hub (browser, etc.) that fails?
There is no automation on the hub, I only created 2 devices that I use meshed to my C7 hub. They show as OFFLINE on the C8 hub.
On the C8 hub the green led remain solid.
No response from the reset switch beneath.
My only option at this point is to unplug the hub.
The reset switch underneath is a network configuration reset. If you are using DHCP already (I think that's the default) you probably won't notice anything when you press it.
Do you have a reservation established on your DHCP server so you receive the same IP address when it reboots?
In a normal situation, If I press the reset switch beneath for 10 seconds, it will get a blue blinking led. In my case when the hub hangs, the reset switch become unresponsive as well.
Yes, I do have a dedicated IP address for the hub from the router.
A big thanks to Hubitat outstanding customer service, they will send a replacement unit.
