All you can really do is see if a "Refresh" causes a "Remove" button to appear, maybe trying once more if not (waiting at least a few seconds after the refresh before waiting to see about "Remove" and a bit more in between attempts, keeping "Logs" open to make sure you don't get any concerning Z-Wave messages); or waiting a day or few to see if "Remove" appears on its own at some point after now.
That, plus knowing that you've actually excluded, reset, or powered down the node, which it sounds like you have. "Remove" won't appear if the node can be pinged.
If this doesn't work, what hub model are you on, and if you're on a C-8 Pro, did you switch to Z-Wave JS? (That might help with this, but it's probably not worth switching just for this; it's just worth sharing more about your setup.) A dead node here is certainly good to avoid when you can, but it's not a guarantee of problems, so unless you have any, I'm not sure it's worth worrying about right now. Patience is often key for Z-Wave management.
