old Series 3 Apple Watch won't update to 8.7.1

Hello.

I recently found my Dad's old Apple Watch series 3 that I wanted to start using for myself.

I went ahead and charged the watch until it had gotten to 100%.

I then wen't in and unlinked the device from my dad's apple account and then erased all of the watches content and settings so it was completely fresh. The next thing I did was try and link the watch to my iPhone 12 Pro (running IOS 16).

I have been trying to update the watch for over 24 hours and have tried nearly everything that is suggested online. The download takes ages and the time ranges from hours to "7 days". The furthest the update has gotten is to the "Preparing update" stage of the download. When I get to preparing, the process starts over and the watch downloads the update again. I have tried turning both devises off numerous times, erased my iPhones network settings, tried on and off wifi multiple times, etc.

I am unaware of what the current software is on the watch, but when trying to update 8.7.1 watchOS, sometimes the update will halt entirely and say "watchOS 6.2.6 your watch is fully up to date....." and then the 8.7.1 update will restart again but never get past preparing stage.

This is very irritating and I have never in my years of experience with Apple Products had such a difficult time setting up a product. I even let the update sit on all of last night and nothing changed. I'd like to resolve this myself and not have to actually bring it into the apple store if need be.