My first phase (in the Windows Update screen) hung on 92% for many hours (not sure exactly how long because I went to bed but I personally saw at least 8hrs and then was up 5 hours later so 8-13 hours).
After clicking into the reboot phase I think I've seen it reboot a time or 2 but it's on the main "Working on updates" screen and has been at 25% since almost 5 hours ago.
I have extremely fast net (1Gb) I have an extremely fast system disk with plenty of extra space (M.2 NVMe ~1/2TB free) and plenty of ram (32G).
There is absolutely NO acceptable reason why it should take this long for *any of these phases. What is the update doing under the hood that takes so long? I could probably manually update all of the files myself by hand and it wouldn't take me this long. ???
Updates are Updates and are generally mostly fast my only complaint being that too many of them require reboots these days when Windows was nicely trending towards nearly no reboots before. These "Feature" updates are more like "Service Packs" so I understand they may take a bit longer BUT when we're getting these every quarter or more often that's a TON of time where the host is unusable compared to going through this once or twice a *major release previously.
This has to get better. >:-(