Purchased the Apple Watch 5 in Nov of 21 for a Christmas present, it was an open box, unused device. It took over a week of trial and error including the hard resets and app removals, etc. I had success just today. My network had a 2.4 Ghz and a 5Ghz network; for the last week i have had the phone on the 2.4Ghz band. Just today I connected the Iphone to the 5Ghz network, then started the pairing process once again. Note the apple watch never appeared on my 2.4 Ghz network when my phone was connected to the 2.4 Ghz. At this point the Router network recognized the Apple watch. I assigned it to a home device and rename it within my network. Next I had to list it as a wearable device. This allowed the router network to open communication to the Apple Watch and begin to accept the updates. It appeared for a while that the updates stalled, but after almost half an hour the Iphone said it had another update, then another. It finally finished updating to OS 8.3 and restarted. Now going through the final set-up phase. Hope this helps.